This has been an interesting discussion, and made me revisit what I
identified as a Costa's Hummingbird found on May 26, 2011 in Bend, Oregon.
https://flic.kr/p/dXnAg7
Now I am not so sure. Plain white throat, scrunched up posture, slightly
curved bill; but the wings are shorter than the tail. I'd be interested in
any 2nd opinions.
Craig Miller
Bend
On Sat, Jan 23, 2016 at 5:37 PM, David Irons <llsdirons@xxxxxxx> wrote:
Matt Hunter's follow-up with this interesting smallish-looking hummingbird
is a great cautionary tale. Matt shared Julie Edmonds' photo of the live
bird with Shawneen Finnegan and me several weeks ago and both of us
concluded that it was most likely a young Anna's Hummingbird. Over the
years, I've seen a number of paler below, smallish, short-billed immature
Anna's misidentified as Costa's Hummingbirds, thus I am always wary when I
see reports of female Costa's. Often times the only reason given for the ID
is that the bird "was too pale below and looked too stubby and short-billed
for an Anna's."
When right out of the nest–and Anna's are essentially year-around nesters
in Oregon–young Anna's are noticeably paler and less greenish-gray below
than adults. They tend to have shorter-looking bills, which if seen
close-up have the growth corrugations that Matt describes in his analysis
at the link below. In my experience, they tend to look shorter-tailed as
well, which contributes to a more scrunched-up or stubby appearance.
As a general rule, the bill of Anna's is straight, while the bill of
Costa's is slightly decurved. Otherwise, if you look at both the text and
photos in the Peterson Guide to "Hummingbirds of North America" by Sheri
Williamson, you will see nearly identical descriptions for the females and
immatures of these two species and although the photos of spread tails show
a bit more white on the tip of R3 in Costa's, the text describes the amount
of white on R3 exactly the same for both species. The differences in the
measurements in the table that Matt created are not likely to be noticeable
in the field unless perhaps you had the two species side-by-side for
comparison. For this reason, reports of out-of-range (i.e. Oregon) Costa's
should be accompanied with very high quality images. There are surely many
young Anna's and female/immature Costa's that are inseparable in the field.
Dave Irons
Portland, Oregon
If you want your voice to be heard, please write to or call your elected
officials,
because they won't know what you want unless you tell them.
---------- Forwarded message ----------
From: "Matthew G Hunter" <matthewghunter@xxxxxxxxx>
Date: Jan 22, 2016 11:11 PM
Subject: Careful with Calypte
To: "ub" <umpquabirds@xxxxxxxxxxxxx>, "obol" <obol@xxxxxxxxxxxxx>
Cc:
I investigate an intriguing female hummingbird:
http://umpquabirds.blogspot.com/2016/01/careful-with-calypte-in-december-2015.html
Matt Hunter
Melrose
