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Sunday, August 24, 2008

Shake A Tail Feather

My yard has had the expected push of female/immature-type hummingbirds for the last few weeks, so I decided to deploy my Wingscapes BirdCam in attempt to remotely capture images of the birds. It is nice getting bird photos even when I'm off teaching, birding somewhere else, or sleeping in!

Figuring out adult male hummingbirds isn't too big a deal, but dealing with females and youngsters can be a little trickier. One thing I noticed in the images as I reviewed them were significant differences in tail patterns. Many guidebooks don't help much in this area, but page 278 in the 5th edition of National Geographic has a nice comparison plate featuring the spread tails of Broad-tailed, Rufous, Allen's, and Calliope Hummingbirds. Steve Howell's Hummingbirds of North America, The Photographic Guide is also an invaluable reference for sorting out these hummers. So to set the theme, here's a little tune from The Blues Brothers (Shake a Tail Feather.)





The first subject is a Broad-tailed Hummingbird. True to its name, note the wide tail, with a bit of rufous in the inner corners:

Broad-tailed Hummingbird

In profile, this hummer shows a moderately long, slightly curving bill along with a warm wash on the flanks (described by Howell as vinaceous-cinnamon!) I think this is an immature bird, perhaps female, based on the throat spotting pattern and what I think is a lack of a contrasting forecollar (which an immature male would show better.)

Broad-tailed Hummingbird

Next up is an immature male Rufous Hummingbird. Here we see extensive rufous throughout the basal half of the tail, spilling into some of the uppertail coverts. How do we rule out Allen's? Well, for one I'm in Colorado, where that species has yet to be documented. I expect Allen's to turn up in the state, however, and it is going to be a photo like this that proves it. Perhaps a hummingbird bander will get the shot, but I wouldn't rule out digital photography of freely flying birds like this. You can see the strongly notched tip to R2 (the second tail feather out from the middle), diagnostic for male Rufous. Additionally, R4 & R5 (the outermost tail feathers) would be even narrower than these in male Allen's.
Rufous Hummingbird

Beyond the tail pattern, notice the overall chunky look of the bird, bull-necked and with a fairly short, straight bill (giving a much more compact appearance than the Broad-tailed.) A nice rufous wash on the flanks and white forecollar also mark the immature male Rufous.

Rufous Hummingbird

The third species I commonly get coming to my flowers and feeders is Calliope Hummingbird (North America's smallest.) The last of our tail patterns today, you'll notice no rufous in this individual (though a wee bit near the base is present in some birds.)

Calliope Hummingbird

Beyond that, this diminutive hummer has a short straight bill and a funny pot-bellied look. I think they are shaped kind of like a bowling pin. Also, note it isn't nearly as warmly colored on the flanks as either of the preceding birds.

Calliope Hummingbird

3 comments:

Mary C said...

Very helpful information, Bill. Now all I need to do is retain this info when I see other hummers other than my usual Anna's.

Jackie said...

Oh, that reminds me how much I miss John Belushi!

Con Daily said...

This is more ID information than I find in the bird ID books, even the strictly hummingbird books. Notch in the tail feather? I'll be looking for it! I still have a few of the hums around, the young rufous and broadtail, but the calliope are rare visitors at my place. They'll all be gone soon.