WatchList Species Account for Clark’s Grebe
(Aechmophorus clarkii)


Qualifies for the list as a Declining Yellow List Species

 

Clark's Grebe

Photo: USFWS

Originally included with Western Grebe and considered color morphs of a single species, the Clark’s Grebe differs from the former only in the number of notes it utters in its otherwise identical mating ritual, and in details of its bill color and facial pattern. These slight differences are enough for individuals to recognize their own species and to mate only with one another; suspected hybrids between the two are relatively uncommon. Because the split into two species is relatively recent, the literature treats the two as a single species.

 

In range, Clark’s and Western Grebes overlap broadly, in breeding found widely in western North America and in winter primarily along the Pacific Coast. The two species are also resident in the Mexican Plateau. The two species breed on freshwater lakes and marshes with open water, often sympatrically. The Clark’s tends to dive less frequently than the Western, probably correlated with its tendency to forage in deeper waters. Populations of the two may be declining but no thorough survey is available.

 

The grebes were once shot for their plumage, with some large colonies nearly wiped out; pesticides and drainage of lakes for agriculture have also decreased the populations. Colonies are subject to disturbance by human recreationists, particularly in motorboats, which render easily accessible areas unsuitable for the birds. Management using water control structures to manipulate emergent growth can benefit the birds.