Anna's Hummingbird in Boulder

[David Tønnessen]

Birders,

It appears an Anna's Hummingbird was reported in Boulder County yesterday, as a Ruby-throated Hummingbird. See the description from the list:

https://ebird.org/checklist/S98074548 

Best,

David Tonnessen

Colorado Springs

[David Tønnessen]

I was asked to explain why this bird is an Anna's Hummingbird. I'm going off of two general things; structure, and plumage pattern. Structurally, it's chunky for a hummingbird. By plumage, first note that the dark feathers in the throat are colored iridescent feathers (a gorget). The pattern fits for a female Anna's Hummingbird over young male Archilochus hummingbirds. Also notice how the GRAY underparts transition gradually to greenish flanks and back. The pale areas of the throat are also grayish. In Ruby-throated Hummingbirds, these areas (throat and chest) would be very white, contrasting more with the rest of the bird. The same would be true for Costa's Hummingbird. Anna's Hummingbirds lack a bright white chest that most other hummingbirds in the US show. Another thing pointing away from Costa's Hummingbird is how far down the throat the iridescent pattern reaches.

In the third photo, one of the iridescent throat feathers is angled right to show color. Pink, like in Anna's Hummingbird.

Best,

David Tonnessen

Colorado Springs/Boulder