Pied-billed Grebe

New York Status: Threatened
Federal Status: Not Listed

Description

The pied-billed grebe is a small waterbird measuring approximately 11 to 15 inches in total length, with a 20 to 22.5-inch wingspan and average weight of just 0.75 to 1.0 pound. Males are larger than females but both share similar plumage characteristics. They are dark brown with a black throat patch, and the sides of their neck and flanks are grayish-buff. The tail is a short tuft of wispy feathers with white undertail coverts.

Their name comes from their most distinguishing characteristic: the pied, or two-colored bill which is bluish-white with a distinct black vertical bar on either side. The bill is short, laterally compressed, and slightly hooked downward. Grebes are built for water with legs situated far back on their bodies to assist diving for food. This type of anatomy makes walking on land awkward and difficult; therefore, you'll rarely see them out of the water if you're lucky enough to see them at all!

The pied-billed grebe is a secretive bird and is generally heard more often than it is seen. It is most vocal during the breeding season in late April and May. The vocal array is variable but is most often a repeated series of soft and slow to start caow, caow, caow notes that build in volume and speed, followed by a series of long, whining kaooo notes.

Life History

The pied-billed grebe's wintering range extends from the southern U.S. to Central America and parts of South America, where they occupy open lakes and rivers, estuaries, and tidal creeks. They return to New York between late March and mid-April. Pair formation may occur on wintering grounds, during migration, or on the breeding grounds. Shortly after their arrival on breeding grounds, the pair builds a floating platform nest in open water or within stands of tall, emergent vegetation, such as cattails. The nest is made up of soft, flexible vegetation from the pond or lake bottom and leaves clipped from the water surface. The average clutch size is six eggs with one egg laid per day. Incubation generally lasts for 23 to 24 days. Chicks can swim for a few minutes at a time within the first day of hatching but spend most of the first week riding on the adult's back. Time spent on the water gradually increases over the next four weeks until the young are feeding independently.

The pied-billed grebe diet typically consists of fish, crayfish, and aquatic insects which they collect during underwater dives. Fledging occurs 30 to 60 days after hatching; however, independent young may remain in small groups with their siblings until they leave for the wintering grounds between September and November.

Distribution and Habitat

The pied-billed grebe is the most widely distributed grebe in the Americas. It ranges from southern coastal Alaska across mid to southern Canada, throughout the U.S., Central America, and the Caribbean, and south to central Chile and southern Argentina. It breeds on freshwater to brackish seasonal and permanent ponds. It requires dense stands of deep water emergent vegetation (e.g., cattails) for nesting and cover that are situated close to open water for foraging. In New York, pied-billed grebe breeding records are scattered across the state but are most abundant in marshes associated with the St. Lawrence River Valley and Lake Ontario.

Status

Population numbers most likely coincide with the availability of suitable habitat. Long-term declines were noted between the 1960s and 1990s in many parts of its range due to loss of wetland habitat and residual effects from exposure to DDT and other pesticides. The pied-billed grebe is considered endangered or threatened in many states, particularly in the northeastern U.S. However, wetland conservation and restoration efforts have helped to boost pied-billed grebe numbers in recent years.

The 2000-2005 New York State Breeding Bird Atlas noted a 47 percent increase in distribution from the 1980-1985 records for the species, particularly in the St. Lawrence River Valley and Lake Ontario marshes. Conversely, results from a Canadian study during the mid 1990s through mid 2000s showed significant declines across the entire Great Lakes Basin, particularly in the Lake Ontario marshes. These conflicting results illustrate the difficulty in assessing population trend data for secretive, marsh-dwelling species.

Management and Research Needs

A coordinated National Marsh Bird Monitoring Program is underway that will allow biologists to determine population increases and declines for focal species across their ranges. Surveys that specifically target secretive marsh birds are necessary because marsh birds are rarely detected on traditional bird survey routes, such as the Breeding Bird Survey.

Local changes in population are often associated with changes in habitat. Pied-billed grebes rely on large wetlands with "hemi-marsh" (an even mixture of emergent vegetation and open water) conditions that are deep enough for underwater foraging. Managing large wetland areas of suitable hemi-marsh habitat will attract pied-billed grebes and, hopefully, will prevent further population declines.