What are the threats to Maine staging areas?
Shoreline development and associated human related disturbances
Migrant shorebirds have a limited period of time at a staging area with limited foraging space, therefore behavioral disruptions during foraging or roosting will interfere with needed weight gains or cause shorebirds to move to less productive areas.
Human disturbance affecting migrant birds is a conservation issue of international importance. Increased human development of coastal landscapes for homes, recreation, and commercial ventures, has reduced the available foraging habitat of coastal birds. Studies have revealed that shorebirds were more affected by the presence of humans than any other group of waterbird and people within 100 meters is a significant contributer to decreases in foraging time and positive energy flow. Structures with associated noise and lights within 250 feet can be disruptive to feeding and roosting shorebirds. Studies recommend buffering direct visual contact between birds and disturbances.
- Docks and Marinas. There are several problems with docks located within shorebird habitats including shading, erosion, leaching/spilling of chemicals, and physical alteration of the habitat. Shorebirds will not forage under or near such structures. Accumulation of docks in a cove will make that cove no longer functional for feeding shorebirds due to associated disturbances and habitat alterations. Shorebirds need to feed throughout the entire low tide cycle, shoreline docks will prohibit their feeding on the first and last mud available on either side of the high tide.
- Contaminants. Because shorebirds have high metabolic rates and experience periods of rapid weight gains and weight loss they are very susceptible to the effects of contaminants. Certain contaminants can interfere with their metabolism and navigational abilities.
- Sewage outfalls and river discharge. Sewage outfalls and river discharge can result in organic enrichments, freshwater flush and sedimentation, and diminishing invertebrate concentrations.
- Predators. Many predators are associated with increased coastal development such as raccoons, fox, dogs, cats, and gulls.
Why don't they get used to the people?
There isn't time. Although many species are able to habituate over time to human presence and even take advantage of it, like gulls, shorebirds coming from the arctic are only on a staging area for 10 - 20 days and do not have the time to acclimate to people and their activites. Shorebird species have different tolerances to disturbance, black-bellied plovers and piping plovers are very suseptible to impacts from disturbance whereas semipalmated sandpipers and sanderlings are a little more tolerant of human activities. All shorebirds are negatively impacted by humans and/or pets moving quickly within 300 feet of the birds.
