What do waterfowl need and what threatens their habitat?
Waterfowl populations are limited by reduced nest success, juvenile survival, and adult survival, which can all be directly related to the quantity and quality of breeding and staging wetlands.
Therefore, to maintain a healthy waterfowl population, a diverse system of wetlands and undeveloped adjoining uplands is vital.
Waterfowl are a diverse group of species with many requirements.
Nesting
Some species use shallow, heavily vegetated wetlands for feeding and brood rearing, while nesting in the upland forest or grasslands. Other species use deeper water habitats where they dive for food and nest on floating vegetation. Some species, such as Wood Ducks and Common Goldeneyes, nest in tree cavities on the wetland edge and in the uplands surrounding the wetland. To find a suitable nesting cavity, Wood Ducks will often use trees hundreds of yards away from the wetland edge.
Aquatic invertebrates (food)
During spring and summer, hens and ducklings forage extensively on aquatic invertebrates. Abundance and type of aquatic invertebrates are greatly influenced by water chemistry, which is directly related to activities surrounding the wetland. Protein from aquatic invertebrates is used to produce eggs by the hen and aids in growth of ducklings. Therefore, reducing the availability of aquatic invertebrates through water pollution can reduce the waterfowl productivity (ducklings/hen) of a wetland.
Disturbance from human activities
Another important aspect of habitat quality is the level of human disturbance associated with a wetland. Nest success may be impaired and habitat use may be reduced due to pedestrian or boat traffic or other human development near nesting and brood-rearing habitats.
Black Ducks are less tolerant of human disturbance than other waterfowl species such as Mallards or Canada Geese, and so otherwise-suitable habitat may be lower quality for Black Duck breeding due to encroachment by humans. Black Duck use of wetlands in central Maine was negatively associated with human habitation in view of the wetland.
