As if to compete for attention with the “Classic Western” I photographed on June 5, this Clark’s Grebe paddled slowly not far from shore, turning this way and that to be sure I got its good side. It even treated the photographer to an open bill shot showing its tongue.
As readers who studied Grebes 101 already know, the Western Grebe and the Clark’s Grebe are both big birds, indistinguishable in size and body shape. Until 1985, they were considered the same species. Then DNA studies showed significant differences. The visible difference is all in the head. The Western’s bill is a muddy, smoky mix of yellow, gray, and green, and its dark feather cap extends below its eye. The Clark’s, as these photos show, has a clear yellow beak, and it wears its cap clear of the eye. The two species are often found in mixed flocks. Scientists say that interbreeding occurs but is rare.
Oddly, Wikipedia has no entry for John Henry Clark, after whom the bird is named. It says only that Clark was a 19th-century American surveyor, naturalist and collector. Beyond that, an internet search goes blank. Very unusual.