Date: 10/28/19 2:37 pm
From: Caleb Centanni <caleb...>
Subject: [obol] Re: Costa's/hybrid Hummer: Notes and sources request
Hi all,

Looks like my link doesn't work. Here is a new one:


On Mon, Oct 28, 2019, 12:53 PM Caleb Centanni <caleb...> wrote:

> Hi all,
> Two excellent birders have written that a Costa's can sing an Anna's song.
> We weren't aware of this yesterday, and the sources we have consulted
> indicate otherwise. We would love more information!
> This is why we came to our conclusion: The Costa's type hummingbird opens
> its mouth and sings a song which matches Anna's Hummer almost exactly for
> me. Anna's Hummingbird is one of my 10 or 20 most familiar birds. I have
> seen 4 Costa's ever.
> With that being said, while declaring the bird as a hybrid was perhaps an
> overly quick call, we have yet to find a source online that records Costa's
> singing an exact Anna's song. Does anyone know of a source, online or in
> the literature that records this phenomenon?
> The reason we made this call was because none of the apps or websites we
> checked for recordings had any documentation of Costa's singing an Anna's
> song. Courtney also has Hummingbirds of North America by Steve Howell,
> highly recommended to her, which states that hybrids will look more like
> Costa's and sing an Anna's song or intermediate.
> So let's help each other in figuring this out if we can: What sources do
> we have with info on Costa's singing Anna's songs, and what field
> observations are there of this? We don't have a BNA subscription, but a
> preview from Google says young males Costa's can sing a similar song to
> Anna's but 'fainter and less sustained'. This bird sang at full volume
> several 12-second songs in perfect Anna's tone. You can hear this on our
> recordings. Our recordings of the bird's chase calls also sound similar to
> Anna's.
> We would of course love if this turns out to be a pure Costa's
> Hummingbird! We just are trying to represent the truth of the situation in
> the best way we can. Let us know what you think?
> Also, if anyone knows hummingbird experts and would like to send the
> photos along (Nolan took some great ones yesterday), that could be helpful
> too.
> The checklist now has our recordings:
> Good birding,
> Caleb & Courtney

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