UPDATE: Re: Hybrid Aechmophorus grebes; Clark's x Western

Mike Bush

Hi Again,

Kevin Zimmer has contacted me separately with his thorough review of my photos:

By the way, in looking at your photos, I’m not at all convinced that you have a mixed-species pair.  The bird on the left has a typical orange-yellow bill for a Clark’s, and although the black feathering of the crown comes farther down on the face than it does on its mate, the bottom of the eye is still bordered by white feathering.  That’s how many Clark’s Grebes look in winter, and could be indicative of a sexual difference.  A Western Grebe should have dark feathering below the eye, and the bill should be greenish-yellow, with an extensively dusky culmen.  At best, the bird on the left is a hybrid, but I would still vote for it being a Clark’s Grebe.

On Sat, Aug 15, 2020, 14:21 Mike Bush <mbushii@...> wrote:
Hi All - 

Seeing great photos coming from the breeding grebes at Santa Margarita Lake, I made the journey from Los Osos on Thursday and Friday early mornings and was NOT disappointed! The floating nests are as close as 30'-50' feet from shore, and there were noticeable activities as well as chicks.

While there was much camaraderie among old pals and new bird-friends, there was not much discussion in my presence regarding hybrid grebes - in fact Clark's Grebe was only separated from Western Grebes in 1985. Apparently however, the two species may interbreed, although rather rare. In reviewing my photos from Friday, I can clearly see a Clark's and a Western tending the same chicks.

Photos HERE

Mike Bush
Los Osos, California