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> Wildlife > Species Information > Maine Endangered Species Program > Maine's Bald Eagle > Biologist's Journal (2006)
The Biologist's Journal (2006)Narratives on bald eagle ecology, species recovery, and conservation issues through the year in conjunction with Maine’s bald eagle nest “Web camera” during its first year at a nest in coastal Hancock County. We applaud Wing Goodale and co-workers at BioDiversity Research Institute (Gorham, Maine) for this initiative. Many collaborators aided the project. Dedicated to the millions of Internet viewers of the “eagle cam” during 2006 and our mentor of bald eagle recovery in Maine: Francis J. Gramlich (1910 – 2006). co-authored by:
Biologists’ Journal: 2006 IndexJanuary 17 - Year-round residency January 17, 2006 notes: Year-round residency.An adult bald eagle flies in to watch from a shoreline pine 100 yards from the nest as our field crew completes today's installation of the surveillance camera. The nest is often a center of activity (feeding platform, foraging lookout, overnight roost, etc.) even in the "off-season." Past surveys of wintering eagle distribution revealed frequent use of nests across Maine. Year-round residency is especially prevalent near ice-free coastal waters but occurs even in northernmost interior Maine. Eagles use wintering areas habitually but can patrol a wider area or relocate in response to changes in winter severity and food availability. We found during Mark's research that there may be steady numbers of wintering eagles in a locality, but individual eagles sometimes move broadly across the state or into neighboring New England states. Management comments: Today's visit was timed to avoid impacts to breeding eagles, but we did not escape their attention. Bald eagles are year-round residents of Maine. Adults appear frequently near nests in all seasons. A territorial presence (even in midwinter) is both a deterrent to other eagles attempting to move in on established nests and an advantage to finding food in familiar foraging habitats. The winter diet influences the fitness of eagles that will soon initiate breeding during March and April.
Charlie Todd, Maine Department of Inland Fisheries and Wildlife February 6 notes: A visitor!An immature bald eagle landed in the nest today (see image below). Often called "juveniles" (a term better used for first-year birds) or "young" eagles, immatures are brown-feathered over the entire body with variable white mottling patterns. They do not have the white head and white tail of an adult bald eagle: the highly distinctive plumage that signifies sexual maturity. The buffy highlights in this visitor's head plumage, light feathering of the throat area, dark beak, and brown eye color suggest that it is a second-year bird. It's possible to age immature bald eagles by focusing on these features since head plumage, beak color, and iris color all change in predictable patterns through the first 4 years. Patterns of white on body feathers can be quite varied. Immature eagles are not smaller bodied than their adult counterparts. This bird could be a visitor to Maine or a native. We have identified eagles from as far away as Florida, Michigan, and Saskatchewan spending time in Maine! Nest intruders may be briefly tolerated at this time of year. Territorial adults usually rudely escort them away during the nesting season, even if is an offspring from previous years attempting to visit home. Only once in more than 50,000 observations of nests here in Maine have I witnessed breeding adults allowing a visiting immature eagle to land on an active nest. Management comments: Non-breeding eagles (especially immatures) often have a nomadic lifestyle for the first few years but tend to return to their natal area as they approach adulthood at 4 - 5 years of age. Immature eagles from Maine have been seen along the Atlantic seaboard from Nova Scotia to South Carolina. Death rates of eagles are higher in their early years due to inexperience and wide-ranging habits. Charlie Todd, Maine Department of Inland Fisheries and Wildlife February 9 notes: Adult eagles return!Both adult eagles appeared in the nest today. They likely were never far away. Visits to the nest and the duration of their stay should increase steadily over the next 6 - 8 weeks prior to active nesting (commences with egg-laying). Even when not visible in the nest, one or both are likely keeping a watchful eye from a sentry perch nearby. Check your audio settings if you are watching the eagle 'cam via live-streaming video. You may hear the shrill vocalizations of adult eagles perched locally. Many are surprised by the sound of an eagle call! I live one-half mile away from an eagle nest in Penobscot County and can sometimes hear the adults vocalizing around their nest while inside my home: often before sunup or during the early morning hours when many birds are most active.
Management comments: Mid-February is traditionally the start of the sensitive period for nesting eagles in coastal Maine. Although bald eagles sometimes acclimate to human activities, new disturbances or abrupt seasonal changes can cause breeding failures or permanent abandonment of nests. Seasonal safeguards are a key to coexistence with nesting eagles. The timing of nesting events is generally a month later in northern Maine, and therefore the onset of the sensitive period is March 15 there.
Charlie Todd, Maine Department of Inland Fisheries and Wildlife February 15 notes: Nest site loyalty.Both adult eagles are making multiple appearances daily at the nest. They feed at the nest occasionally, but meals can be eaten anywhere until food deliveries to young nestling eaglets become necessary. Rearrangement and grooming of small sticks and vegetation lining the center of the nest command most of their attention: apparently readying the nest for eggs.
This is the 11th consecutive year of eagle residency at this site. Construction of this nest began in October 2005. In just 10 seasons of use, the nest has grown to a two-level structure: each measures 3-4 feet in width and depth. The lower level appears to be residual debris from the original nest that partly fell after damage to supporting limbs. Our eagle 'cam is usually zoomed in on the "top floor" portion of the nest to optimize views of upcoming breeding activity. Management comments: Bald eagles are notorious for being highly selective of nest locations. Some Maine nests have been used for more than 35 years and thus were likely home to 2 - 3 generations of breeding eagles. The annual addition of nest materials can lead to enormous structures over time. A Sagadahoc County nest measured 20 feet tall and 7 feet across when first discovered in 1963; it was estimated that eagles resided there for 60 years or more. Even when nests must be relocated to a new tree, the alternate nest is often built nearby. Their loyalty to traditional nesting habitats is the basis for effective land conservation initiatives, environmental regulations, and stewardship efforts of landowners. All habitat protection strategies have proved important to eagle recovery in Maine. Charlie Todd, Maine Department of Inland Fisheries and Wildlife February 28 notes: nest buildingFor the last two weeks (since about Valentines Day) this pair of eagles has been sprucing up their home! The web cam provided a unique vantage point to watch this rarely-observed behavior. Check out the archived still photos during this period to observe bald eagle housekeeping. Nearly every morning, both eagles were busy carrying branches to the nest. The female (larger eagle) seems to be the interior decorator and spent the most time arranging the sticks. After two weeks of persistent work, they raised the nest platform about 6 inches. In the last few days, they began carrying small twigs and grass to line the nest bowl. Curiously, nearly all eagle nests contain a sprig of white pine in the nest bowl. We think this is nature's remedy to deter parasites like feather mites. I've observed bald eagles on the ground in February gathering grass for their nest - an odd behavior for a regal bird that spends much of its time soaring high above the earth. I've also observed eagles snapping large branches from pine snags while in flight and often wondered, "What happens if the branch doesn't break?" They seem to have an uncanny ability to judge which branches will snap easily! Bald eagles are the most sensitive to human disturbance at the final stages of nest building and just prior to egg-laying. Activity close to the nest can result in nest abandonment. Mark McCollough, U.S. Fish and Wildlife Service March 6 notes: incubation begins!The eagles completed nest building last week. For several days they carried grass, sprigs of pine, and other fine materials to line the center of the nest. After home improvements were finished, the female began lying prone in the nest for short periods of time. Late last week the duration of incubation behavior increased, and we knew that egg-laying was not far away. She remained prone for 30% of the time during a 4-hour period on February 27, but periodic absences indicate that eggs had not yet arrived. Bald eagles have spectacular courtship displays in the weeks leading up to egg-laying. They soar to great heights, lock talons and cartwheel at dizzying speed to the earth, breaking apart just before they hit the ground. They may chase each other, lock talons, roll together in the air, and continue their tandem flight. These behaviors are part of an annual courtship ritual to strengthen the pair bond and encourage mating. Copulation may take place on the nest or a perch nearby. During the last week, we often heard the eagles vocalizing from the nest tree, but out of view of the camera. Our eagles were discreet, and we didn't observe mating. We suspect the couple spent a romantic weekend somewhere on the coast of Maine!
By the morning of March 6, both birds were at the nest for extended periods of time but still left for varying intervals. Charlie stopped at the USFWS office that afternoon to pick up several eagle carcasses sampled by Steve Mierzykowski, our contaminants biologist. We tuned into this web site and were thrilled to see that the female had resumed incubation posture in the nest. A clear, starry night revealed the adult's white head in that same position long after sunset. Nothing had changed by first light March 7. It seems certain an egg was late on March 6! Management comments: Some observers of nesting eagles get the mistaken impression that they are no longer present when, in fact, incubation is underway. One member of the pair is almost always attending the eggs and out of view. Its prone posture is usually not visible from below. The mate may be ranging widely for food or watching nearby but is also less conspicuous to most. Seasonal privacy near the nest is their priority and a good strategy for those who want to co-exist with nesting eagles. Mark McCollough, U.S. Fish and Wildlife Service and Charlie Todd, Maine Department of Inland Fisheries and Wildlife March 13 notes: Time for diligence.After only a week of watching incubation, perhaps you can see the strategy of nesting eagles is simple, patient diligence to one duty: keeping eggs warm enough to hatch. The incubation period of approximately 35 days requires steadfast attention. For intervals of only a few minutes, the eggs may be unguarded as one adult takes a break and its partner soon resumes the task. The interval during an incubation exchange was 5 minutes long on March 11, an unusually warm spring morning in coastal Maine. During cold spells and spring rain or snowfall, the incubating eagle must endure the elements to safeguard its egg.
Look for subtle behaviors in this period. An adult may rise up, step around the eggs, and reach down to roll them with its beak. If a prolonged absence is planned, a departing adult may cover its eggs with nest lining before departure. When resuming incubation, the female is likely to almost go face down before settling into a position where its brood patch is pressed snugly against the eggs. This is a thinly feathered area on the upper breast enabling an incubating bird to transfer most of its body heat to the eggs. Incubation duty is not as easy as it sounds. On March 12, I watched an incubating eagle at a Penobscot County nest sit tightly while a crow perched on the edge of the eagle nest: an apparent attempt to lure the incubating eagle into aggressive pursuit and perhaps allow other crows nearby to predate the eagle egg(s). This eagle did not budge, and its mate appeared after a 10-minute standoff to chase away the crows. Raccoons and fisher may also climb into lofty eagle nests for eggs or nestlings, and biologists may prescribe a predator guard to deter them. Management comments: Eagles have varying levels of tolerance to intrusions. If you or I get too close to a nest, an incubating bird may abandon its primary mission of egg care to circle the nest vicinity (often with an exaggerated flapping flight: not the typical, effortless soaring) and vocalize in protest. This behavior can be misinterpreted as "the eagles are putting on a show for us" when, in fact, they are imploring you to leave. Please do so! Charlie Todd, Maine Department of Inland Fisheries and Wildlife March 22 notes: Eggs over easy.You may have noticed that the eagles occasionally take a brief respite from incubation and seem to arrange items in the middle of the nest. Eagles, like all birds, need to turn their eggs frequently during incubation. An air cell forms in the egg shortly after the egg is laid and grows larger during incubation. The parents need to turn the egg to prevent the developing embryo from adhering to the eggs shell, which stops development. As far as we know, biologists have not documented how often eagles turn their eggs. Perhaps you can gather some information on this behavior by watching the web camera. Bald eagles typically lay only one clutch per year. Eagles on the coast of Maine may lay a clutch as early as mid-February, although early March is more typical. In northern Maine, where the lakes are still frozen over and the snow pack still has weeks before it melts, egg-laying may be delayed into early to mid-April. We have seen eagles many times blanketed in an early spring snow, but remaining faithful to their incubation duties. Bald eagles lay one to three eggs, but two is most common. They are dull white in color and about the size of a goose egg. The eggs are laid about 3 or 4 days apart. Incubation begins when the first egg is laid, which means that eggs in a clutch will hatch several days apart. "Asynchronous hatching" is a common in strategy in birds of prey. One chick will always be the oldest and largest and dominant over its siblings. In poor food years, only the oldest chick may survive, but in good years all chicks in a brood survive.
Both male and female eagles develop a brood patch - a bare area of skin in the center of the chest to keep the eggs warm. The female eagle does most of the incubating, but the male also returns to the nest to help. If you're lucky, you may see a nest exchange occur on the web camera. The male will often bring food to the nest for the female while she is incubating. Adults show great concern for their fragile eggs and walk very carefully around the nest with clenched feet to avoid breaking the eggs. We would be interested in hearing from you if you observe no eagles on the nest during the incubation period. Adults will occasionally leave the eggs for a brief time (perhaps on warmer days in late incubation). If they do, they sometimes cover the eggs with grass and pine needles from the nest bowl to avoid predation by crows. Mark McCollough, U. S. Fish and Wildlife Service April 4 notes: Hatching one week away?This morning there is a brisk southeast wind blowing across the Gulf of Maine and buffeting the stand of pines along the shoreline where the nest is located. The web camera, mounted on an adjacent tree, is having trouble staying centered on the eagle nest. A cold rain will fall later today, and we may even see snow by afternoon. How will the inclement weather affect the eagles? The first eagle egg is due to hatch about April 11 (plus or minus a few days).
Bald eagles are one of our earliest nesting birds in Maine. Only great-horned owls nest earlier. We have a relatively short "time in the sun" here in the north and eagles need to get an early start nesting so they have enough time to incubate their eggs (35 days), raise their young to be able to fly (10 to 13 weeks), then allow the young to perfect their flight skills (another 6 to 12 weeks) before leaving their parents in the closing days of summer. Our eagles laid their first egg on March 6, but we've documented some pairs incubating as early as mid-February. Sometimes we've observed eagles incubating their eggs with all but their heads covered in a late-winter snow. Long periods of adverse weather can have a detrimental effect on the nesting success for eagles. Last year was a good example when we endured one of the coldest and rainiest springs on record. In 2005 we documented 385 breeding areas occupied by paired eagles. Of those, 48% (183 nests) hatched eggs, well below the 58% average success rate we've experienced in the last 15 years. The poor weather not only affected the hatching of eggs, but also reduced chick survival. The longest period of heavy rain occurred in May when chicks were still in the downy stage and have difficulty keeping warm without the constant attention of their parents. In 2005, 253 eagle chicks fledged from 183 nests. Eagle biologists use the ratio of chicks fledged to successful nests, or "brood size," as one of our important measures of the productivity of the population. Last year brood size was only 1.38 chicks fledged/successful nest, nearly 7% below the average for the last 15 years. This year our spring weather has been unusually mild and dry: perfect conditions for nesting eagles. Charlie Todd and other state biologists have begun their initial aerial monitoring of all known nest sites in the state and occupancy of eagle nests looks good. Barring no major weather events, we may see a downy chick in the nest next week. If past odds are a guide, we have about a 60% chance that this pair of eagles will hatch one of their eggs. Keep your fingers crossed! Mark McCollough, U. S. Fish and Wildlife Service April 9 notes: Precious eggs near hatching?We are all eager to detect hatching at the nest this coming week. The adult eagles have faithfully tended their egg(s) for nearly 5 weeks. The incubation period for bald eagles is "about 35 days!" Very young nestlings may not be visible initially from our camera angle so watch eagle behaviors closely. There is a subtle difference between the prone posture of an eagle incubating eggs and the slightly raised (but very low) position of one brooding an eaglet. If there is more than 1 egg, hatching dates are days apart identical to the interval between egg-laying dates. In other words, an adult in the nest has to perform both tasks in this challenging time frame! The first clear evidence of a successful hatch will either be a glimpse of the young eaglet or observations of feeding motions to an unseen, tiny hatchling. Look for food morsels being passed "beak to beak" from the adult to an eaglet. We have discussed the impacts of disturbance and inclement weather on nesting eagles, but there are many other risks. One that once jeopardized bald eagles across most of their range in the continental U.S. was chronic breeding failures from environmental contaminants. DDE (a by-product of the insecticide DDT) once caused widespread eggshell thinning and breakage before hatching. In the 1960s and 1970s, only 30% of eagle nesting attempts in Maine yielded eaglets. At the time, levels of DDE were higher than any other findings in wildlife tissue sampled in the U.S. The photo below shows the 1974 transplant of eggs not impaired by DDE into a nest in midocast Maine. Frank Gramlich and Paul Nickerson (both now retired from the U.S. Fish and Wildlife Service) were attempting to bolster the supply of eaglets where eggs failed to hatch at all local nests in the Kennebec River estuary during a 16-year period. It helped hold eagles in areas where the species was nearly extirpated. A limited supply of "precious eggs" was brought in a thermal suitcase from a captive breeding program in Maryland or healthy donor populations in Minnesota and Wisconsin. Paul Nickerson, former endangered species coordinator in the Northeast, recalls egg transplants during 1974-76. Paul brought 3 eggs from Minnesota's Chippewa National Forest in 1974. Only one of 3 attempts succeeded that year. Addled eggs taken from each nest revealed high levels of contaminants. Egg transplants were about 40% successful. In later years, eaglets were fostered into nests with contaminated eggs. This technique was 90% successful. Desperate circumstances required extreme measures as the decline of Maine eagles continued well into the 1970s. Our "eagle cam" was placed at this Hancock County nest partly because this location has the best nesting record of any nest in Maine since it was first used in 1995: 100% of ALL nest attempts here have been successful. Eighteen eagles have taken first flight here over the last 11 years: nearly double the average nesting productivity among Maine eagles. Other nests are less fortunate, and some have continuing problems with environmental contaminants like PCBs and mercury. Another pair of eagles nesting only 30 miles away from the "eagle cam" represents the other extreme. Eagles nesting there have NEVER raised eaglets during 12 years of breeding at a remote location free from disturbances. Most nests in Maine have nesting statistics somewhere between these two extremes. Since 1996, 60% of all eagle nesting attempts in Maine yielded eaglets that survived to fledging. Some of the 40% failures in the population are due to environmental contaminants. We hope that this problem does not arise at our "eagle cam" nest, and toxics never again threaten the population. Management comments: Bald eagles are a top-level predator and therefore exposed to concentrated doses of environmental contaminants passed through food webs. Beginning in the mid-1940s, several raptors and fish-eating birds like bald eagles experienced dramatic declines for nearly 3 decades during the height of the DDT era. Banned in 1972, there are still residues in most eagle tissues in Maine, but the impact of DDE has diminished. Mercury and PCBs still harm some Maine eagles. These contaminants can transport through the atmosphere exposing other regions. Maine is downwind from prevailing westerly winds in North America. Most people value bald eagles as our national symbol or a magnificent part of our wildlife heritage, but their role as an indicator of environmental quality cannot be understated. Charlie Todd, Maine Department of Inland Fisheries and Wildlife April 12 notes: We have a hatch!Charlie Todd's wife, Barbara, saw a small head peak out from under the adult eagle's wing on Wednesday, April 12. Later, at least two little guys were briefly visible in the nest! As Charlie mentioned earlier, this is one of the most successful eagle nests on the coast of Maine, and they've done it again! One adult will brood the chicks almost constantly for the first few weeks because young eaglets are covered only by a light down coat. They are susceptible to cold and rainy weather as we are experiencing right now. Last year's heavy spring rains and exceptionally cold temperatures reduced nesting success statewide, but the population should recover quickly from these random events.
To give you an idea of what a hatchling looks like we've attached a picture of a day-old chick that Barbara raised in 1978. The egg came from a nest on Swan Island (Sagadahoc County) and unexpectedly hatched in an incubator following fostering of an eaglet there. The Swan Island eagles had not hatched their own egg in at least 20 years. Twice, we introduced an egg or eaglet from a captive breeding facility in Maryland to bolster eaglet numbers locally. This young eaglet was raised in captivity until 4 weeks old and then fostered back into another eagle nest where the adoptive adult eagles raised it to fledging! Young eaglets can only eat very small items so the adults will tear up food into bite-sized portions and gently offer it to the chicks. As with many birds of prey, eagle chicks don't hatch at the same time so one eaglet is larger than its sibling(s). If food is scarce, the oldest eaglet out competes others for food and survives, while smaller sibling(s) may not. With ample food, all nestlings will fledge. Food availability has a great deal to do with nest site selection, especially during the nestling period. The presence of anadromous fish, such as alewives, often enhances brood size (the number of eaglets in a successful nest).
Management comments: Food quality is important during this early nesting period. Coastal eagles feed much more on birds, especially fish-eating birds such as gulls and cormorants, than do our inland nesting eagles, which eat a much higher proportion of fish. The result is that our coastal eagles have a greater chance to accumulate contaminants such as DDE, PCPs and mercury. Luckily DDE is rapidly disappearing but the other toxics are still present influential. Bucky Owen, University of Maine emeritus April 17 notes: Two eaglets in our nest!This morning after a prey delivery, we watched the parent eagle feeding two chicks. She meticulously reduced the prey to small morsels and carefully fed both chicks. One chick is older and larger than its sibling and is the first to be fed. The smaller chick will continue to do well as long as plenty of food is available. Sibling competition for food and mortality from starvation or infanticide is greatest in the first two weeks when the size difference between the two chicks is greatest. For most of the time, the chicks will remain out of view of the web camera. They cannot maintain their body temperature when they are young and downy. Notice how the parents sit differently on the nest in a more upright posture. On rainy days, the wings of the adult act like an umbrella to keep the chicks dry.
The chicks will remain downy for the next two weeks. At that time, we should start to see some black pin feathers, which will replace the down. If chicks are fed well, they grow about 100 grams per day. Maximum growth occurs when they are about 3 to 4 weeks of age.
For the first two to three weeks after hatching, the female is present at the nest about 90% of the time and the male about 50% of the time (out of view of the camera). You will often hear one of the adults calling to its mate or tilting its head upward to watch its mate soaring overhead. Once the chicks start to grow feathers and can maintain their body temperature, the parents will begin perching off the nest. Bald eagles are extremely sensitive to disturbance at this critical time. To flush an adult eagle from the nest exposes the chicks to cold, wet weather or predators. When we review development projects, we always request that activity near the nest during the incubation and early chick-rearing period be avoided. Mark McCollough, U. S. Fish and Wildlife Service April 23 notes: Triplets (3 eaglets hatch!)Several astute observers of our live-streaming video recently reported glimpses of a third eaglet. We agree!! Finally this morning, I clearly saw a third fuzzy little head rise above the nest rim. Wing Goodale at BRI captured this great shot from the eagle cam archive tape showing a feeding of the triplets later that day. As Bucky and Mark have both noted earlier in our Biologists' Journal, significant hurdles remain for the survival of all three. Adequate foods for rapid eaglet growth, no disturbances that displace adults from the nest, no adverse weather spells, and low dietary exposure to contaminants are all important to survival of our triplets. Last year, only one nest in Maine successfully reared 3 eaglets to fledging.
For viewers that rely on the still-image updates, extra patience may reveal all 3 young eaglets. There is a slight depression in the nest bowl (the soft lining at nest center) that hides smaller, prone nestlings. Be on the alert at feeding time, because eaglets sit upright and crane their necks upward to be the first in line for feeding. The adults will likely stand to grapple delivered food or may change places with one another: either way, eaglets may suddenly be more visible! Barb called me to attention at 8:20 this morning as the image update revealed a standing adult with its head turned sharply and beak wide open: something is up! Either this is a greeting to a mate (maybe arriving with a meal) or an alarm call to an intrusion. The next refreshed image 30 seconds later revealed one eaglet straining for the first food morsels shred by an adult bent low over the nest. After 2 more image updates, the head of a second eaglet emerged. After an interval of 6 minutes (12 image updates since the first signs of breakfast), the third eaglet wanted a turn! This order of dominance will likely last for another week or two. By that time, larger eaglets should be visible except when being brooded or shaded by a parent. Management comments: The availability of foods is a major influence on nesting outcomes. Nest locations close to the food supply are optimal so nesting along shorelines is always preferable. Notes by Edie Miles, a technician observing a Penobscot County nest during our research years ago, reveal a key advantage of nesting close to the food supply: "I had not seen the other adult for several hours when the female arose from her brooding posture over the eaglet. In one fluid motion, she stood and launched into flight over the river .... returning 30 seconds later with a fish! Not only was she guarding the eaglet in the male's absence, the female was also watching for a fish to rise." When an adult is facing away from the eagle cam at this site, it is scanning adjacent coastal waters and tidal flats. We hope those keen eagle eyes find enough meals for the eagle cam triplets. Charlie Todd, Maine Department of Inland Fisheries & Wildlife May 4 notes: "and then there were two..."Regular observers are aware by now that only the oldest two of three eaglets now occupy the nest. From notes submitted to this web page about six days ago, the largest chick likely killed the youngest. We've been watching closely to see a third chick, but haven't for almost a week. As we reported in our biologist's notes, siblicide is a natural occurrence for bald eagles and other birds of prey. What you are observing on the web camera is unedited, unfiltered, real-time nature: survival of the fittest. If you have been lucky enough to observe a feeding bout, you have a sense of the intense competition between the siblings.
Fish, birds, and other animals are being killed by the adults several times daily to feed the hungry chicks. At this age, the adult eagles are still feeding the chicks, but soon the chicks will start to learn how to feed on their own. Adult eagles require about one pound of food each day. The demands of both adults and growing chicks require several pounds of prey are procured daily. Predation is a natural part of the cycle of life. Life in the nest can be a tough experience and we may loose other chick(s) before this nesting cycle is completed. I just finished watching a feeding this afternoon. The oldest "A" chick is noticeably larger and more aggressive. Naturally it elbowed its way to be fed first. The "B" chick is smaller and had to wait its turn, but both received a full meal. Both of the remaining chicks seem to be growing at a normal rate. You can determine if the chicks have been fed recently by looking to see if their crop is full. The crop is a food storage organ, which when full creates a bulge at the top of the chest (just under the beak). Adult eagles often consume dead animals (or carrion), which are often too large to carry away. The crop allows birds of prey to consume a large meal and fly elsewhere to digest at their favorite perch. We received an interesting inquiry from Maggie, a second-grade observer from Bangor, Maine, about eagle cleanliness. After feedings, watch for young eaglets to back up to the edge of the nest to defecate. This is the eagles' way of keeping a clean nest. The whitewashes, or “mutes” as they are called, begin to cover the ground below the nest along with a collection of fish carcasses and bird feathers. The adult eagles still rearrange sticks in the nest and toss uneaten carcasses over the side. Some of the uneaten prey gets buried in the nest bowl. The chicks are getting to an age where they may play with an eider duck wing or fish tail. As the chicks get older the nest platform will be well-trampled by their activity. The adults will continue to freshen the nest periodically with a sprig of white pine.
What kinds of prey are these bald eagles bringing to the nest? We'd like to hear about your observations. For years, we gathered food remains at the base of eagle nests to better understand eagle diets in Maine. Over the years, Charlie Todd identified 64 different species of vertebrates. Fish made up more than 75% of remains and were the predominant prey at inland nests. Coastal sites relied more heavily on birds and mammals. When we installed the web camera in mid-winter we found the remains of eider ducks and cormorants at the base of the nest. Coastal eagles feed at a higher level on the food chain than interior birds. Fish-eating ducks (like mergansers) and cormorants have higher contaminant loads than fish. Thus, our coastal eagles have a greater likelihood of accumulating contaminants like PCBs and DDT. Even at this age, the young chicks in this nest already have detectible contaminants in their blood. They received some contaminants in the egg, but are receiving additional contaminants from their food. We will write more about contaminants and how they affect eagles in future biologists’ notes. Mark McCollough, U. S. Fish and Wildlife Service May 8 notes: Bald eagle nesting surveysFor the last 25 years, Charlie Todd, eagle biologist with Maine Department of Inland Fisheries and Wildlife, has completed annual surveys of Maine's eagle population. (In fact, he's in the air flying as we write this!). Eagle surveys yield vital information on the size and distribution of the population. Survey data are crucial for conservation programs and are used to track the recovery of the population. Surveys also provide important information on the health of the population - how many young are born, where we might recover an addled egg for contaminants tests, or where nests are located in relation to developments. Eagle surveys are done with and amphibious float plane twice each year. The first flight begins in March on the coast where eagles nest earliest. These flights extend into May in northern Maine where we often still have snow on the ground this time of year. Observers develop a "search image" for eagles and their nests as indicated in the photo above. With practice, the white head and tail of the bald eagle can often be discerned in a white pine at quite a distance. Eagle nests are large, and sometimes snow in the nest bowl in late winter will reveal the location of a new nest. Bald eagles most frequently nest in our state tree, the white pine. Sometimes eagles will take over an osprey nest. Eagle nests are usually under a canopy of branches, and biologists have to search carefully - a difficult proposition when flying at 120 miles an hour. Sometimes we observe eagles flying along a lakeshore or coastline. From a distance we'll circle in the airplane, watch the birds, and follow them to a new nest location.
Eagles mate for life, and many pairs use the same nest year-after-year. The flight plan always calls for checking known nests first. If a pair is missing, we may spend time searching the nearby stands of pine for a new nest. Nests are abandoned for a number of reasons - disturbance the year previous, a mate change, or a nest damaged by a winter storm. The public notifies the state and federal agencies of new nests and eagle activity in areas where eagles had not been observed before. These tips are very helpful in finding new territories. When "deadheading" from one territory to the next, we often ask the pilot to skirt a lakeshore. Every minute in the air counts, and often new nests are located in this fashion. All nests with an adult pair present or incubating are considered "occupied." In the photo below, one eagle is in an incubation posture and the mate is perched nearby. In June, all occupied nests are surveyed a second time by airplane to document how many chicks were produced. We try to time the second flight when the eaglets are about 8 weeks or older. At this age, the chicks are starting to get their brown feathers. Most of the chicks observed at this age will survive to fledge later in the summer. As we've observed with the web camera, attrition can occur between hatching and fledging.
Sometimes special flights are made to survey nests more intensively, especially when documenting the age of eaglets for banding or locating unhatched eggs. Several paper companies in Maine are helping the state and federal agencies to monitor contaminants in nests close to their paper mills. These nests are flown every week early in the nesting season to search for abandoned nests with unhatched eggs. Biologists collect unhatched eggs to measure contaminants. We have to promptly retrieve unhatched eggs. Crows and other scavengers quickly consume eagle eggs not attended by the parents. Flying is interesting, but hard work. State and federal pilots have to be well-trained and experienced to fly all day at low altitude and in tight turns around the nests. Biologists have to maintain their concentration and data-taking skills despite working under high G-forces in a loud, hot cockpit. Sometimes, on breezy or turbulent days, Charlie and I crawl out on to a lakeshore or tarmac for a lunch break and wish we could walk home rather than face an afternoon of more flying. On the positive side, we've seen nearly all of the state of Maine, and the scenery and wildlife sightings are incredible. The pastel blush of trees leafing out on the mountains and hills of Maine in May rivals the riotous fall colors. As our population continues to climb, there may come a time when we can no longer afford to fly every eagle nest annually. The U. S. Fish and Wildlife Service and U. S. Geological Service - Biological Resource Division are developing a new survey protocol that samples a random, representative sample of the population. If the bald eagle is delisted from its threatened status, we may begin this survey methodology in the future. Charlie Todd, Maine Department of Inland Fisheries and Wildlife and Mark McCollough, U. S. Fish and Wildlife Service May 15 notes: Is it time to take the eagle off the Endangered Species List?All endangered species biologists hope that sometime in our career we will have the satisfaction of saving a species from extinction. After all, recovery of imperiled species is our highest work priority. We put our heart and soul into these efforts. Sadly, we spend more time adding species to state and federal endangered species lists that taking species off. State and federal biologists and many other partners have been working diligently to save the bald eagle since it was added to the first federal endangered species list in 1967. When Rachel Carson wrote her book Silent Spring about the dangers of DDT and other pesticides in our environment in the early 1960s, bald eagle populations had declined to fewer than 800 pairs in the lower 48 states. Eggshell thinning and embryo mortality from DDT extirpated bald eagles from most of the Northeast, and their last stronghold was a tiny enclave of 27 pairs in Down East Maine. In 1972, the federal government banned DDT. In 1978, the bald eagle was listed as endangered in 43 of the lower 48 states. As DDT began to slowly diminished in the environment, numerous recovery programs were initiated to save our national symbol including purchasing nesting habitat, research to address threats, and restoring eagles to former habitat. The bald eagle quickly became a poster child for the growing movement to save endangered species, and the effort paid off. By the 1980s, bald eagle productivity slowly began to improve, and some populations increased at rates exceeding 10% annually. Today, the bald eagle population has grown to over 7000 pairs in the lower 48 states. In 1995, eagles were "downlisted" from endangered to threatened status. Today biologists believe that bald eagles are secure enough to remove them entirely from the federal endangered species list - a real conservation success story. In February 2006 the U. S. Fish and Wildlife issued an official proposal to delist the bald eagle. You can read all about our delisting plans and the amazing recovery of the bald eagle at a new bald eagle web site. Bald eagles in Maine increased from 29 pairs in 1962 to 385 pairs in 2005. This represents a growth rate of about 7-8% annually. Although impressive, eagle recovery in Maine still lags behind other regions. DDT takes much longer to break down in our cold, northern soils, and we still find traces in unhatched eggs. A healthy eagle population produces an average of one eaglet per active pair. Maine did not achieve that milestone until 1998, and even in recent years we often fail to meet that benchmark. Other contaminants, including mercury, PCBs, and dioxin are still of concern and likely depress productivity in some parts of the state. Despite the lower productivity, survival of young eagles is good and our eagle population continues to increase and expand to occupy their former habitat in northern, western, and southern Maine. At the time of European contact, Maine likely had more than 1000 pairs of eagles. We believe that we still have the habitat to support over 600 pairs of eagles, and the population will continue to grow. Maine Inland Fisheries and Wildlife has met all of the state recovery goals for eagles, except one - to secure a "safety net" of 150 nesting areas in conservation ownership, easements, or cooperative agreements with landowners. Loss of waterfront habitat to development is a persistent threat that needs to be addressed if we are going to continue to support a vibrant population of eagles in Maine. The state is close to meeting its nesting conservation goal, and it is likely that Maine will remove the bald eagle from the state list in the near future. What happens to a species after it is delisted? Do delisted species still get any protection or conservation funding? Both the U. S. Fish and Wildlife Service and Maine Inland Fisheries and Wildlife will continue bald eagle conservation efforts long after Charlie and I retire. Once the bald eagle is delisted the Bald and Golden Eagle Protection Act (BGEPA), passed in 1940, will provide a level of protection for eagles similar to that provided by the Endangered Species Act. The Eagle Act protects bald eagles from take, possession, or sale of a bald eagle or its nest. As part of our delisting proposal, the Service developed a definition for what it means to "disturb" a bald eagle in the BGEPA and issued draft national bald eagle nesting management guidelines. We are seeking public input on our delisting proposal and changes to the BGEPA. Comments from the public will be accepted until June 19 (see the web site above for all the details concerning the delisting proposal). Also, after the eagle is federally delisted, the Service is committed to funding at least 5 years of population monitoring. Charlie and I have both participated in developing new eagle monitoring surveys that will ultimately be used to monitor the health of the eagle population in the lower 48 states for decades to come. If the eagle, or any other delisted species, begins to decline, we always have the option of placing it back on the endangered species list. With continued conservation we hope that populations continue to grow and the eagle will never need to be listed again. There are many who deserve credit for the recovery of the eagle in Maine. We thank landowners who voluntarily (and sometimes adamantly) protect "their" eagle nest and sometimes make significant sacrifices to do so. The Maine Chapter of The Nature Conservancy, Maine Coast Heritage Trust, and many other local land trusts have helped protect a "safety net" of eagle nest sites. The Land for Maine Futures Program and federal expansion of the Maine Coastal Islands National Wildlife Refuge helped purchase many coastal eagle nesting islands. We owe a debt of thanks to Dr. Ray "Bucky" Owen, professor emeritus and former Department Chair at the University of Maine wildlife program, for advising a succession of graduate student research projects that helped to address the threats facing eagles in Maine. Federal biologist Frank Gramlich, who recently passed away, led Maine's early efforts to protect eagles, especially when populations were on the brink of extinction and threatened by a major oil refinery proposal on the coast of Maine. Perhaps more than anyone else, Charlie Todd, MDIFW eagle biologist, deserves much of the credit for recovery. Charlie came to Maine as Bucky's first eagle graduate student 29 years ago and has led Maine's eagle recovery ever since. It’s rare that a biologist has the opportunity to participate in a species' recovery from the dark hours of listing to the success of recovery, but Charlie has been there to participate in recovery from beginning to end. Maine's bald eagle habitat protection program is nationally recognized and has struck a successful balance between protection and private land stewardship.
There are hundreds more to thank for the recovery of eagles in Maine, but the common thread in eagle delisting is that we can save wildlife from extinction if we all work together toward a common cause. Each of you has something to contribute to help endangered species, whether it is purchasing a conservation license plate, joining the local land trust, or communicating with your representatives in Congress about the importance of the Endangered Species Act. “Make endangered species a vivid presence in the lives of people. Make it clear that every endangered species has a name, has a million-year history, and has a place in the world. Bring us face-to- face with each of those species. Make us know that they are companions in the biosphere. They are not just something out there you look at once in a while, but they're part of our existence...they are part of us.” -- E.O. Wilson This is what we hope to accomplish in our careers as endangered species biologists. We hope this web site helps bring this conservation message home to you. Mark McCollough, U. S. Fish and Wildlife Service May 25 notes: Bald eagle researchers in Maine.I want to give all of you a brief history of three folks responsible for eagle research and management in Maine since the late 1960's. Frank Gramlich was the man who encouraged many of us to work with eagles in the early days. Frank just passed away last month. He was a WW II veteran and returned to the University of Maine (UM) for his B.S. and M.S. degrees in Wildlife Management. He then worked for the U.S. Fish and Wildlife Service (USFWS) for 22 years. He had a passion for raptors, and you could always find a menagerie of birds in various stages of repair in his barn. Frank began the first systematic aerial survey of bald eagles in Maine in the late 1960's with Bill Snow, a federal warden pilot. Frank also established a voluntary landowner agreement to help protect nesting sites. In addition, he initiated the egg transplant program and later the transplant of young eaglets into unsuccessful nests in Maine. He and I became friends in 1970 and he encouraged me to seek funding for a graduate student (Charlie) to study the status of Maine eagles. In early 1980, Frank and I were expert witnesses for the USFWS against a proposed oil refinery in eastern Maine, the location of the last vestige of eagles at that time in the northeast. In Boston, Frank was ruthlessly examined by a team of lawyers for six hours and had significant medical problems because of that event. The EPA judge was later removed for his conduct of the hearing, but Frank never recovered his health. Frank served on the Northern States bald eagle recovery team and was our mentor for more than 30 years. Charlie Todd was that new graduate student fresh from the Virginia Commonwealth University who was assigned the job of determining the status and distribution of Maine’s population (nesting and wintering), breeding ecology, influences on reproduction, food habits, and everything else about Maine eagles! Truly a monumental task and worthy of a Ph.D., but Charlie just wanted a M.S. degree. State and federal biologists, citizen volunteers, UM honor students, technicians, and many more all pitched in to make his a classic study. He “finished” in 1979: a timely year for bald eagles which had just been designated an “Endangered Species” in Maine and 42 other states the previous year. His thesis was scrutinized by attorneys and scientists embroiled in the 1980 oil refinery controversy. It was at a time when our population and nesting success was at rock bottom and Charlie pulled it all together for us and charted a path for recovery. At that time every eagle was priceless and we went to extremes to return every injured bird back to the wild. The picture below of Charlie holding an immature eagle illustrates this. We taught one legged eagles how to forage, rebuilt wings (with the help of local falconers) using feathers from dead eagles, repaired broken bones and then returned all of these birds to the wild. Bart, a male eagle with a lost wing, went into every classroom in Washington and Hancock Counties, as part of an education program. Perhaps the toughest job Charlie had was conducting a winter survey of eagles along the entire coast of Maine, thousands of miles of flying. We wanted to know if there were particular concentration areas that needed special protection. It was long and very dangerous work, and we had two pilots on board at all times. Flying at a few hundred feet, following the coastline around islands and peninsulas was flying at its very worst. We hired several technicians who made it from Bangor to Ellsworth before we had to land and call a car to pick them up! On the other hand, we finally found Tim Stone, who would sit in the back of the plane and eat onion and liverwurst sandwiches and be in heaven! Charlie went on to join the nongame and endangered species group of the Maine Department of Inland Fisheries and Wildlife (MDIFW), where he resides today. No one knows Maine eagles better than Charlie, and he is unquestionably one of the top eagle biologists in the country. We are fortunate to have him directing our state program. Since he is still up flying I can sneak these comments onto the Blog without his editing!! Mark McCollough came to UM from Penn State. He completed a M.S. studying shorebird migration in eastern Maine and then joined me on a Ph.D. project looking at the population dynamics, particularly survivorship, of eagles. As we obtained more contaminant data on eagles and their eggs, it became obvious that we could not influence nesting success in the near term, except to reduce disturbance at nest sites. DDE was slowly working itself out of the system and it was only a matter of time before its influence would decline (as we have already seen). On the other hand, we had some of the highest PCB and mercury (Hg) levels in the country. PCB's are banned and should decline slowly but Hg is still coming in by air from the large power and industrial centers in the Midwest. Hg accumulates in fish. Our inland nesting birds feed more on fish than our coastal birds, thus Hg is more of a problem on inland lakes. EPA and others have been reluctant to impose tighter restrictions on air emissions thus our problem continues. Better air quality from the Midwest is crucial to better human and wildlife health in the northeast. But back to Mark: We knew that most of our immature eagles left Maine in the fall and returned in subsequent years. They were accumulating contaminants that influenced their future breeding success. What if we could provide ample clean food to our young birds and keep them here in Maine? This should improve their survival and improve breeding success in the long run. So Mark established several feeding stations along the coast where we delivered 100,000's of pounds of clean food over a series of years. Mark ran the show: collecting beaver, deer, moose, cow, horse, chicken, etc. carcasses, butchering and distributing them. Stories abound like losing a truck load of chickens on the main street of Ellsworth but Mark kept tons of carrion flowing! To see how effective the feeding program was Mark built observation blinds at the sites. All winter long he'd crawl into these before dawn, wrap up in a sleeping bag, and observe birds with high power telescopes. Immediately he realized he could read the band numbers on the legs of the eagles. We had been banding all of the nestlings in Maine for several years so he was able to get a handle on who was out there. To facilitate this we added specially numbered band tags and an additional band on the other leg. We did this for several years and Mark was able to read these numbers easily. To Mark's surprise and our joy we found that the youngsters were remaining in Maine and surviving at a much higher rate than we had anticipated. Mark was able to show that this was a key factor in initiating our population recovery. At the feeding station Mark was able to read the band numbers of eagles from Cape Breton Island, Chesapeake Bay and as far away as Saskatchewan! Eagles were mixing over large geographic regions, an important genetic consideration. Mark went on to join Charlie in the endangered species/nongame group of MDIFW and recently joined the USFWS as an endangered species biologist here in Maine. We couldn't ask for a better pair of biologists looking after our endangered species. Bucky Owen, University of Maine emeritus
June 7 notes: Banding eagles.From our eagle surveys, we now know the web cam eaglets are among the oldest in the state. Their baby down is rapidly being replaced by dark brown contour, wing, and tail feathers. The feathers grow from blood quills, which you can see at the base of the large wing feathers in the last picture posted above (they look like a blue drinking straw). Young eagles are chocolate brown in color. They do not get a pure white head and tail until about five years of age. Their beaks and iris are dark brown and will not start to turn yellow for another 2 or 3 years. Both eaglets are growing rapidly and likely weight about 6 to 8 pounds - about 1/2 to 2/3 the weight of their parents. At this time the chicks are starting to exercise their wings, but they have to be careful or they will damage the blood quills. The wing beating exercises will increase in frequency in another week or two when their wing and tail feathers are fully developed and harden. As observers have noted, the adults are rarely within view of the web cam, but they are nearby hunting and guarding the nest. You've also noticed that we have been getting a lot of rain in Maine in the last two weeks. These chicks are likely old enough to tough it out without Mom's help, but I've seen them often huddled together to keep warm. Younger chicks don't fare as well. We've already documented several advance-aged chicks that died in other nests during our aerial surveys. Since the early days of eagle recovery, biologists in Maine and elsewhere have used banding as a technique to learn about the movements and survival of bald eagles. When we band eagles we secure a small, individually-numbered metal ring or band on the legs of eagles to individually identify each bird. The birds wear the band for life. Eagles seem to get used to the bands like a ring on a finger. In the 1980s, we attempted to band all bald eagles in Maine and New Brunswick. For over a decade tree climber extraordinaire Bernie Thompson of Brewer, Maine climbed every eagle nest with young. Bernie climbed his last eagle nest several years ago when he approached his 70th birthday. This June, tree climbers Bill Hanson and Chris DeSorbo (pictures below) are climbing nests in interior Maine as part of a study to evaluate the effects of mercury and organochlorine contaminants on eagles. (The eaglets at the web camera nest will not be banded.) Climbers use boot hooks, ropes, and safety equipment to climb trees. Although bald eagles are a large bird of prey, they do not defend their nest or attack the climbers. The adults often circle overhead and vocalize while the climber is in the nest. The climber gently places the 4 to 6 week-old eaglets in a canvass bag and slowly lowers them to biologists on the ground. Each chick is weighed and measured. Blood and feather samples are taken for the contaminants analysis. The metal bands are secured loosely around the leg and riveted in place. A red band with a large letter-number combination is a unique identifier for Maine eagles (other states and provinces each have their own assigned color bands) and aids with identification of birds from a distance. A standard U. S. Fish and Wildlife Service band has a unique number stamped into the band. The chicks are then hoisted back into the nest in the canvass bag. We gather prey remains at the base of the nest to learn more about eagle diets. The entire process takes about an hour.
Important information is learned from banding. Band numbers are retrieved from dead or injured eagles, and sometimes band numbers are read and reported by eagle watchers. Banding provides information on eagle movements. We've had eagles from Maine recovered or observed in as far away as Labrador and South Carolina. We've seen eagles in Maine banded from as far away as Saskatchewan, Nova Scotia, and Michigan. Repeated observations of banded eagles over the years are used to estimate survival rates of eagles. As part of my doctoral research, I read the band numbers from hundreds of eagles visiting winter feeding stations with a spotting scope and used the information to document survival rates for young and adult birds. Banding also provides information on how old eagles live in the wild. Recently we recovered an adult eagle 23 years after banding it as a chick in the early 1980s. We do not band all the eagle chicks in Maine each year. Although biologists in some states routinely band all of their eagle chicks, we only band the birds for directed studies. We are no longer reobserving eagles at winter feeding stations to document survival rates. This summer, eaglets at selected nests are being banded in conjunction with a contaminants study.
Mark McCollough, U. S. Fish and Wildlife Service June 26 notes: "Fledging any day now..."Our young eaglets are growing fast and now look like real eagles. "Big" (as many of you like to call the largest bird), was hatched on April 10 making him or her 11 weeks old, and "Little" is about 4 days younger. Both eaglets are approaching the size and weight of their parents. In fact, young bald eagles have longer wing and tail feathers than their parents (biologists don't know why).
As astute viewers have observed, the adult eagles are rarely seen now except to make a quick prey delivery to the nest. They don't bother to tear the food apart, but allow the eaglets to carve up their food with their sharp beaks. Usually, the adults are within site of the nest (or perched out of view of the camera high in the nest tree). Adults on the coast of Maine have feeding territories up to a mile or two away from the nest depending on the location of feeding areas and competition from nearby nesting pairs. About two weeks ago our eaglets started "limbing out," that is leaving the nest and perching on adjacent limbs. They don't go far from the nest and remain in camera view. Don't be surprised to see them start to fly/hop from limb to limb or nest to limb. Watch for the eaglets to grasp hold of a limb or the nest and beat their wings vigorously. This behavior accomplishes two things - first, it strengthens their wing muscles in preparation for their first flight, and second, its gives the birds a good sense of the size and power of their wings. It takes considerable agility for bald eagles to fly in and out of trees with a 7 foot wingspan, and these pre-flight routines help them gauge their own size. On breezy days, watch for the eagles to extend their wings and float briefly into the wind before settling down on the branch again. Sometimes they will snatch a branch from the nest and float into the air with the limb in their talons. A large portion of the day is spent preening (adjusting and oiling) their new feathers.
"Big" could make his or her maiden flight any day now. I studied the "fledging" phase of bald eagle ecology years ago as part of my doctoral research at the University of Maine. Young bald eagles make their first flight at 11 to 13 weeks of age. What makes a young eagle decide to leave the nest? After watching about 20 eagles fledge, I can't say for certain. I never saw the adults encourage the young to fly or to entice them away with a food item; Charlie saw that tactic once. Just like kids, I believe they just know when its time to try out their new wings! On many occasions I witnessed the first, awkward flights of a young eagle. I recall that many times this occurred during one of their floating-into-the-breeze experiments when they missed the branch or got blown by a gust of wind. Suddenly, they realize they are airborne with nothing but a great void underneath them! The young eagles don't know the art of soaring and thermals, so they begin flapping vigorously. Since eagle nests (like this one) are located near water, the first flight is along the shoreline over a lake, ocean, or river. Usually, the first flight is no more than 200 to 500 yards. The shoreline environment provides many opportunities for landing - a log or rock on the shore, low trees, or maybe a large white pine. I've seen young eagles land in the water and row to shore with their wings. More often, they try to land in a tree. On several occasions I watched young eagles land on branches only to have their momentum carry them forward so they end up hanging upside down with wings extended like a giant bat. On other occasions I've seen them tumble from branch to branch in a tree until they desperately grasp a perch or talon full of twigs to stop their fall. Adult eagles don't seem overly concerned that their young have fledged. "Big" will squawk and squeal at its parents when it gets hungry or if it sees the adult returning to the nest to feed "Little." A week or two after fledging, the adults will start to deliver food to the fledged eaglets in nearby trees. Although it is difficult for eaglets to learn how to grasp a fish with one foot and hang on to the tree with another. I've seen many a disappointed fledger hang their head in discouragement after fumbling and dropping a fish just delivered by its parents. Fledging is a dangerous time for young eagles. They can get injured during their first flights. Sometimes, boaters will encounter an injured eaglet and bring it to us for rehabilitation. They are also vulnerable to predators. Young eagles that land on the ground will "climb" a tree by evening by hopping upward branch by branch. This gets them out of the way of ground predators like raccoons and foxes. Don't be surprised to visit the webcam in the next week and only see a single eagle in the nest. "Big" could go any day. Once eaglets leave the nest, they usually develop the flying skills (or hunger) to make the flight back to the nest within a few days. The nest will remain a center of activity for the eagle family through the summer and serve as an easy landing spot for future feeding. Mark McCollough, U. S. Fish and Wildlife Service June 30 notes: The trials & tribulations of fledgling eaglets." ... one bumbling tumble for bald eagles ..." Yes, astute observers of the eagle cam witnessed a less than stellar exit from the nest by our smaller eaglet about 4 pm EDT today, June 30. I have to be honest: I didn't see it, but a barrage of phone calls soon confirmed that this complicated process of flight is underway at the eagle cam! Many are concerned for its fate because this maiden voyage looked more like a flop / fall than a flight. Fear not: I called a neighbor who sees the bird on a limb beneath the nest, while "big sister" remains in the nest. As Mark described in our last Journal entry, nothing surprises us about first flights, first landings, and the entire early fledging period. It is indeed a high risk time, and therefore, perhaps more compelling to watch. We have zoomed out the camera to give a wider angle view of the entire nest and surrounding lateral limbs of the nest tree so perhaps more of the process will be in view for those who dare to watch! Actually, all is going well at the eagle cam. Here are some brief notes from other nests around Maine to give you a taste of the many challenges faced by nesting eagles: A Sagadahoc County nest had triplets when Chris DeSorbo and I visited the nest on May 15. Chris and Bill Hanson combine to band eaglets and obtain blood samples for monitoring dietary mercury. One of the three 4-week old eaglets is smaller than its siblings. Since Maine is planning to donate an eaglet from 3 different nests to a reintroduction in Vermont, we immediately broach the idea of removing one here with the very conscientious landowners who are agreeable. We have to wait to find a "set" of appropriately aged eaglets. Chris visits 3 weeks later and finds only two eaglets: a repeat incident of what happened a few weeks earlier at this eagle cam. The same outcome reduces broods of 3 eaglets at a nest in Kennebec County and one in Waldo County. When food is limiting or harsh elements challenge an adult's ability to care for all nestlings, only the strongest survive. We look elsewhere for eaglet donations to Vermont. A Penobscot County nest with poor productivity has been closely monitored since March as part of special research monitoring dioxins in Maine eagles. It's a priority sampling site for the mercury study as well. Two addled eggs were recovered here in 2005. We are all pleased by their apparent success this year when my May 23 flight revealed two 4-week old eaglets standing in the nest. On a June 1 flight, only scattered remains of both dead eaglets are visible: the victims of scavenging ... or possibly predation. Chris finds two 6-week old eaglets dead in a Washington County nest later in June that were likely killed by another predator. Our climbing crews have now recovered 5 dead eaglets in little over a week. Tissues will be tested. On June 5, wildlife rehabilitator Anne Rivers follows up on a report that 2 eaglets are on the ground at a Hancock County nest. She retrieves them; feeds and rehydrates them for 3 days; and gets a veterinary exam, blood tests, and full body X-ray. I investigate the site and find the nest 100% fallen and a neighbor who has lost 10 hens to predators. The birds would not have fared well here, and they become (by default) our first "volunteers" to move to Vermont. They go home with me and get a 50-mile head start on their 400-mile trip. Haddock for dinner! Good news from other locations: there are healthy sets of triplets at 3 Kennebec County nests. Eagles did not nest in Kennebec County between 1975 and 1994 as past declines decimated eagle numbers near Maine's state capital. One of the triplets is at the last Kennebec nest occupied in 1974 before their disappearance and where eagles returned to nest in 2001 after a 27-year absence. The landowner recalls when "his eagles" were the beneficiary of an egg transplant in 1974. The karma is good, and on June 8 we take the smallest eaglet away to join Maine's donation to Vermont. Bill Hanson climbs the tree on a very rainy day and soon after I am driving away with my wife holding a wet eaglet on the passenger seat so the bird will show up dry in Vermont. Only 10 miles down the road of its 250-mile journey our passenger shifts its weight, does a headstand, and does what all well-fed eaglets do. ("Eagle cam" watchers all know what happens next!) I am plastered by eagle poop at point-blank range. My sympathetic wife eventually stops laughing and orients the eaglet in another direction just in case. The transfer of 3 dry eaglets for Vermont is completed a few hours later. I look for a change of clothes! Here's one final anecdote to show that sometimes we can remedy pending eaglet losses. Chris climbed another Sagadahoc County nest on June 12 and bands a 4-1/2 week old eaglet with large facial inflammations below its eyes. Bill Hanson returned to the nest on June 27 with wildlife rehabilitator / clinician Marc Payne who lanced the swollen sinuses and administered an antibiotic and sutures. It's pretty clear that this bird would not have made it without some help. Management comments: Research at eagle nests and interventions with nestlings is always conducted in small windows of opportunity to minimize risks. Eaglets aged 4 - 7 weeks old can withstand the interruption and brief lack of parental care. Thus, we were not tempted to intervene at the "eagle cam" nest when the third eaglet was lost in just its third week: risks to its siblings could not be justified. Wildlife managers often prescribe timing safeguards to minimize potential disturbances near nesting eagles. The timing and unique circumstances of each location are considered in combination. As you watch fledgling eaglets in the difficult early stages of life out of the nest, please realize that this is another sensitive period when eagle nests can use all the privacy we can afford them. Charlie Todd, Maine Department of Inland Fisheries and Wildlife July 4 notes: Fledging!!!So apropos...our both eaglets fledged on the 4th of July! Jane, one of our viewers provided recordings of both fledging events, which can be viewed at the web links below. I am including Jane's report and Charlie Todd's e-mail response below. No one was in the nest this morning (July 5), but we expect both birds will occasionally visit the nest from time to time over the next few weeks. After they gain better flight skills, they return to the nest as a convenient place to feed and perhaps even roost for the night. After fledging the chicks stay in close proximity of the nest for a month or two before leaving their parents and dispersing from the nesting area. As part of my doctoral research, I observed 18 young eagles during this phase of their life. After fledging, the young birds develop their flight skills, but apparently have no interest in learning how to hunt. After thousands of hours of observation, I never saw a fledged eaglet attempt to forage on its own. They fly from tree to tree begging food from their parents. Eventually, the parents get tired of this game and the young birds drift away from the nesting territory. They must eventually learn how to find food on their own. Where do they go after leaving home? From our banding studies, we know that about 30 to 60 percent travel long distance south along the Atlantic seaboard during their first winter. Young eagles from Maine have often been observed in the Chesapeake Bay region, western Massachusetts, New York, Pennsylvania, and New Jersey. Other fledged eaglets wander around Maine for their first winter looking for easily-obtained food. About 75% of the eagles survive their first year. By their second or third summer, most return to Maine to stay and eventually nest at age 5 or more. Few of our banded eagles are known to be nesting outside of the state. Check in on the nest from time to time. You may be rewarded with an observation of "Big" or "Little." Mark McCollough, U. S. Fish and Wildlife Service Jane: Yes, I saw this comment in the blog -- amazing reception that these birds have had. Publicizing fledging was bound to create lots of concerns. The landowner assures me there is no eaglet on the ground, and I've asked him & neighbors not to search the woods for a potential rescue: better to let the adult eagles take care of that task and assure that the family bond stays intact. It's quite foggy on the coast July 4 - July 5 a.m. so it’s unlikely there'll be much movement there until clearing. I may get to fly surveys in that area today so I will try to get visuals on the birds. -- Charlie -----Original Message----- Subject: videos of Eaglets leaving eagle cam nest I looked at "Little"'s departure very closely on some other video that showed clearly what happened. He flew up, trying to get back in the nest, but he landed on a branch that was way too small for his talons to grasp and get a grip on. When he tightened his talons on it, he spun right around in an upside down position, and then he let go and fell head down. Hope he's okay. Begin forwarded message: July 7 notes: 2 fledglings OK/no rescue needed!Dear friends of the eagle cam' and well wishers for our fledgling eaglets: Take a deep breath, relax, and enjoy continued viewing on the eagle cam'. Both fledgling eaglets are DEFINITELY still present and closely guarded by both parents. After the aerial survey flight was cancelled today, the boss (Barb = my wife!) convinced me that we should carefully patrol the nest vicinity to make sure all is well. By reading your blogs, it's clear that many were tormented by the unknown fate of both eaglets after fledging on July 4. (There's anxiety in our household as well!) Please, never visit an eagle nest where fledglings are freshly on-the-wing unless you are advised by a biologist and know how to handle an eagle in the event of a mishap! We spend most of our time moving cautiously and scanning the vicinity while one eaglet is above in the nest. We do not want to excite it into flight since many fledglings prefer to prolong their homecoming and delay their next flight as long as possible after first returning to the nest. We do not want to scare our missing eaglet -- whether perched in a tree, standing by the shore, or injured and hiding in understory vegetation. Most of all, we do not want to trigger adults into circling flights and vocalizations protesting our presence because this will certainly alarm the entire eagle family. We inspect the area beneath the nest: relieved not to see a dead or injured eaglet. The resident landowner shows us an area of matted grass where something large bedded on the ground for a while. We all remain uncertain. I patrol the shoreline bluff, and Barb walks along the water's edge. At 11 am EDT, one adult flies quietly from a lofty pine 100 yards west. Fortunately, there are no aggressive displays or cries of displeasure. After we pass this perch, Barb briefly glimpses a dark eagle follow the same flight path: a smooth glide with only a few wing beats out of sight and around the shore at least 250 yards away. Was that really the missing eaglet? Is a 2-second observation out of the corner of your eye adequate reassurance? She's not satisfied ... I assume that eagle cam' viewers won't be content either! Part of this process may evolve outside the view of the eagle cam' but I would be shocked if you do not see "Big" and "Little" at the nest during the next 2 months! Their use of the nest will diminish gradually. If they really don't get along that well, they may not spend much time there together. (If we can do this next year, we will band the birds to aid identification, but looking at behavioral tendencies is a good strategy to distinguish them. However, if one eaglet was displacing the other from a preferred perch, habits may change when they have solitary time in the nest.) Adults will purposefully minimize time in the nest so as to encourage development of the eaglets. Sometime in September or October, family ties end. The eaglets disperse. One Maine eaglet appeared as far away as South Carolina by November of its first year! The landowners (gracious hosts of the eagle cam') welcomed our visit, shared insights, and provided delicious lobster salad sandwiches after our mission was complete. They have experienced 14 consecutive years of successful nesting so they have perfected the art of co-existence with nesting eagles. Appropriate stewardship is key to safeguarding the remarkable recovery of bald eagles. After >28 years on the Endangered / Threatened Species list in northern states (>37 years in the southern U.S.), future delisting of bald eagles will lessen some regulatory protection and may result in less frequent survey monitoring. Owners and neighbors of nesting eagles can play important roles. We are eager to assist. Let's hope the other 402 pairs of bald eagles nesting in Maine this year have as much luck in coexisting with humans as these birds! Management comments: National guidelines have been drafted to promote a lasting recovery of bald eagles. In Maine, our annual population monitoring and regulatory protection of nests will continue until the Threatened Species status is removed by the legislature. Our agency will only recommend state delisting after successfully implementing a habitat safety net, which includes a mix of land conservation and stewardship roles of private landowners. Agencies will adjust management strategies after bald eagles are delisted. Your support is welcome. Charlie Todd, Maine Department of Inland Fisheries and Wildlife July 14 notes: Questions & answers.Greetings all! The two fledglings at the eagle cam' are doing well with flights, getting better at landings, and remain highly attentive to food and adult parents. They also seem willing to pose in front of the camera on a regular basis ... so we continue! You have proven to be dedicated and attentive observers. Your blogs have greatly simplified my job by sharing insights with each other. The blog has become part of our daily routine to see how things are going and helps us draft the Journal notes! Bucky and Mark are away this week, so I will use the opportunity to briefly address some of the topics you have raised in the last week.
Charlie Todd, Maine Department of Inland Fisheries and Wildlife July 21, 2006: More questions.There have been several questions about sibling mating and what might prevent it; tough question! In the late 1960's and 70's, when eagle numbers were greatly depressed, there may well have been some interbreeding due to the lack of alternative partners. But that has all changed with literally thousands of immature eagles currently occupying the central and northern Atlantic coastlines. Most of our immature eagles leave Maine their first fall and wander for the next four years, often returning to Maine in the summer months. Others overwinter here when there is an abundant and predicable source of food throughout the winter. For example, here in Orono, at Pushaw Lake, there is a small group of mixed aged eagles that attend the ice fishermen on a daily basis. Anglers regularly place pickerel and perch on the ice for the eagles. Young eagles are mixing continually during these years and it is unlikely that siblings would encounter each other much during this period except, perhaps, occasionally if they visit their natal area. It is also possible that siblings recognize each other after several years and there is some innate process that discourages interbreeding. As with most bird species, female eagles select their male partners. With many species, males have established territories and advertise their wares with colorful plumage, displays and song; females then make their choice. Not so with eagles, pairing appears to occur between their 4th and 5th years during times when immature eagles are continuously interacting with each other. Recent information, based a great deal on osprey research, suggests that the male then escorts his mate to his natal geographic area. She, in turn, does the final nest tree selection. Theory says that since the male is the prime food provider during the nesting period, he makes the territory choice based on food availability. Here in Maine we have a great deal of data on former eagle territories and actual nest trees. In the 1980's and 1990's, as our population grew and new territories were established, we were amazed at the number of old territories that were reoccupied, even 20-40 years after they had been abandoned! Old nest trees, decades after nests had disappeard, were used again. Obviously, there were aspects of these territories that the new male recognized, probably food availability, such as anadromous fish (e.g. alewives). The female, in turn, selected many of the old nest trees that still afforded strong limbs for nest support, easy access, and good visibility. We have limited data on dispersal and nesting locations of our own immatures. One bird Charlie and I banded as a nestling in Ellsworth (Hancock County) ended up breeding along the north shore of New Brunswick. It was 27 years old at its death, the 2nd oldest banded eagle ever recovered! Another breeding eagle we radio-tagged in the Bar Harbor region 15 years ago was banded as a nestling in Michigan and this year, we read the band number of a breeding adult in northern Maine that was banded as a nestling in New York. These are just few examples of the geographic mixing that occurs in our northeastern population. I suspect that it is typical, promotes genetic exchange, and sibling pairing under normal conditions is rare, at best. One last observation highlighting the extent of continental eagle movement was a recording by Mark during his PhD work. He was able to read the band number of an eagle feeding at one of his winter feeding stations in coastal Maine; it was from Saskatchewan!! Finally, who was that bird seen at the nest on July 15th? I suspect it could have been a former nestling from that nest just checking things out once it was safe to come near. The nest has been productive for the last 14 years so there are a number of immatures out there somewhere. If you check our first eagle image from the 5th of February you will see another visitor. Charlie related to me that he has found several fledglings dead under eagle nests (not their own). There is probably some attraction to all eagle nests for youngsters and if they blunder into some resident adults it may be tough going. Our eagles mate for life and are at or near their territories most of the year. The chances of another individual or pair taking over that site would be very rare. Bucky Owen, University of Maine emeritus July 24 notes: Still more questions.How long will the Cam be on? This is really a question for BRI, but I hope the Cam will be on well into August. It partly depends on your continuing observations and the cost. It will be up to BRI to make a decision about the Cam next year. We've already seen a significant drop in the amount of time the fledglings are present at the nest. This is great and as it should be. I suspect that observations near dawn and dusk will provide the best viewing from now on. So keep the observations coming. Concerning news of “Martha:” an eagle living in Virginia and recent recipient of attention. Someone noted that eagle densities are very high in the Chesapeake area as is food but available territories are limited. This will increase intraspecific competition, contests over territory ownership, and lead to injuries and death of some eagles. We observed a similar occurrence on Verona Island (near Bucksport) several years ago. The resident male had a blue wing tag (from Massachusetts) and one spring three adults showed up at the territory; by nesting time “Mr. Blue” had disappeared not to be seen again. Can adults recognize young from previous years? We doubt it as these birds have undergone multiple molts. I think the only reason that the sub-adult was able to approach the nest site recently was that the nestlings had fledged and the adults were not present. Is “Little” getting enough food? We don't need to worry about "Little" anymore: "he" is fine. There is no indication that male fledglings are tended by the male parent, females by the female adult. There are no long term benefits to such a strategy. Are the eaglets eating bones? Mark commented earlier that birds of prey, including eagles, regurgitate pellets composed of indigestible materials such as fur, feathers and bones. When doing food habits studies, we collect these pellets and identify their contents along with other “leftovers” (= usually larger feathers and bones not ingested). That's all for now! Bucky Owen, University of Maine emeritus
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