Photo Credit: Pied Billed Grebe, Mike Carlo/USFWS, Public Domain, https://www.fws.gov/media/pied-billed-grebe-11

Pied Billed Grebe

Podilymbus podiceps

Compiled By Niyati Acharya

Pied-Billed Grebes are stocky waterbirds, 30-38 cm (12-15 in) in length, with short legs far back on the body, short wings, a short tail, flat lobes on the toes, and a stout, thick, chicken-like bill.  The plumage of the Pied-Billed Grebe changes with the seasons.  Their call is only given during the breeding season and resembles a series of “cow” sounds.

Pied-Billed Grebes are poor fliers and must run across the water for several yards before becoming airborne; the head is held low during flight.  Rare individuals have managed to fly as far as the Hawaiian Islands, Europe, the Azores, and the Canary Islands.  These birds can be distinguished from all other grebes by the lack of white wing patches in flight, the chicken-like bill, and, in summer, the black band around the bill.

The Latin genus name for grebe, “podylimbus,” means “feet at the buttocks”, since their feet are located near their rear ends. This body plan, a common feature of many diving birds, helps grebes propel themselves through water.

Pied-Billed Grebes can trap water in their feathers, giving them great control over their buoyancy.  They can sink deeply or stay just at or below the surface, exposing as much or as little of the body as they wish. The water-trapping ability may also aid in the pursuit of prey by reducing drag in turbulent water.

Pied-Billed Grebes forage in water among aquatic plants and beneath mats of floating vegetation.  They usually dive for food, but occasionally pluck insects from foliage, the water’s surface, or the air.  They sometimes feed near moving herons and egrets.  Pied-billed Grebes escape danger by “crash-diving”—plunging with head and tail raised above the belly, making a splash.

Both sexes build a large sodden, floating nest of rotting and green plant material and mud.  The decomposition of plant material generates substantial quantities of heat, up to 11-13C higher than the surrounding water, providing enough heat to incubate the eggs in the adults’ absence.

Currently, the greatest threat to this species is the ongoing alteration and loss of wetlands through draining, dredging, filling, pollution, invasive species and siltation from agricultural practices and roads.  These threats lead to the degradation, isolation, and fragmentation of wetlands and have left many marshes that were too small, or were not part of larger marsh complexes, unsuitable for grebes and other marsh birds.

Pollution and environmental contamination degrade the food web of wetland ecosystems and can impair the reproductive capacity of Pied-Billed Grebes through the process of biomagnification.  Popular organophosphate pesticides used heavily for agriculture have been directly implicated in the death of this species and elevated mercury levels have been detected in some individuals.

Sources include: Mass.gov, Allaboutbirds.org, New York Natural Heritage Program

Photo credit:  [1] Mike Carlo/USFWS, [2] Gentry, George/USFWS, [3] Uecker, Sandra/USFWS, [4] Weimer, Mike