Friday, February 19, 2016

Horned Grebe - Podiceps auritus

On trips to to Bodega Bay we spend a fair amount of time at Doran Beach near the Cypress Parking Lot, a spot where Rich Stallcup often took a group he called the "Native Birders", or Natives. Here shorebirds would mass as the incoming tides pushed them ashore from mudflats further out. Sonoma County Regional Parks wisely chose this site for a viewing platform. The Natives contributed funds for a commemorative plaque, and the spot is known as the Rich Stallcup viewing platform. The plaque is mounted on the hardrail there.


On a Feb 9 visit to Doran the plus tide had covered both the mud bars and muddy, shoreline, so few birds were present. Some Brant foraged on underwater eelgrass and a lone Podiceps grebe actively dove in the shallow water near the shoreline, only 30-40' from the platform.


The buoyant high-riding profile recalled that of an Eared Grebe, Podiceps nigricollis, as did the way the white from the cheek curled up behind the ear. But a look through the scope clearly identified it as Horned Grebe, Podiceps auritius. Two features confirm it as Horned rather than Eared. First (and perhaps the best discriminator according to Kenn Kaufman*) is the area immediately behind the eye. Here on Horned Grebes the white of the cheek is sharply separated from the black feathers of the head, whereas in Eared Grebes the black auricular area behind the eye extends down into the cheek. Secondly, the shape and color of the bill are classic for a Horned Grebe.


As seen in both shots, the tip of the bill is whitish, whereas the Eared Grebe's bill has a dark tip. In addition, the top of the bill (culmen) curves gently down at the tip, whereas most Eared Grebes bills have a flat culmen, giving the appearance of a sharper and upturned bill. Check out the rear mounted feet, great for a diving bird but not much use for walking. Podiceps could be translated at "rump footed" (Holloway). You may have guessed that auritus translates as "eared"!


*Kaufman, K. 1992. The practiced eye. Identifying monochrome Eared GrebesAm. Birds 46:1187-1190

Here's an Eared Grebe, Podiceps nigricollis, for comparison. Nigricollis means "Black-necked", and in Europe they call it the Black-necked Grebe, referring to the color of the neck in breeding plumage.


There are 19 species of grebes in the world, with 8 of them in genus Podiceps. Along our coast we can also see the Red-necked Grebe, Podiceps grisgena.

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