Wild Ideas: The case of the mystery hummingbird   

For the average birder, checking off one more species on his or her life list can be a thrill, especially if that bird is outside its known range. For those of us who do not consider ourselves birders but still love to watch birds, just sorting out common species can be a challenge, and the rarer ones even more so.

A few weeks ago a reader of this column called me about an unusual hummingbird nectaring on her verbena at her farm in Tiger Valley, near the town of Washington. Out of respect for her wish for privacy, let’s call her Kate.

Kate had ruled out the ruby-throated hummingbird, the only hummer that breeds in Virginia in the summer and is quite common here. She hadn’t had a camera handy, but she described the bird she saw, from about “two feet away,” in a fair amount of detail. She said it was green on most of its back and wings but had rich brown coloring on its lower back and tail, with buff coloring on its sides and no markings on its white throat.

 Through a window Harris Hollow resident Beth DeBergh captured these photos of two rufous hummingbirds, either females or immature males, that showed up at her feeders in winter.By Beth DeBergh
Through a window Harris Hollow resident Beth DeBergh captured these photos of two rufous hummingbirds, either females or immature males, that showed up at her feeders in winter.
By Beth DeBergh

When I heard her say “brown,” my first thought was of the rufous hummingbird, named for its reddish-brown coloring. Historically known to breed in the summer in the Pacific Northwest (all the way to Alaska) and overwinter in Mexico, the rufous is still considered rare north of there in the East. But since the 1980s, it has increasingly been sighted, after its breeding period, along the eastern coast and now throughout much of the U.S. and parts of Canada, according to occurrence maps at on Cornell Lab of Ornithology’s real-time, online checklist program, eBird. The rufous is thought to have expanded its winter range because of nectar feeders put out by bird lovers through the winter.

Although I’ve only seen rufous when visiting my brother in Juneau, Alaska, they have shown up in Rappahannock before. As I reported in my Feb. 28, 2014 column, Beth and Jimmie DeBergh, in Harris Hollow, had two different ones show up at their hummingbird feeder in winter, one in 2012 and the other in 2013, both either females or subadults (immature).

Mature male rufous are brightly colored, and have more brown on them than the females, as well as “flaming red” throat feathers, according to All About Birds, so Kate also ruled those out. Mature females and subadults, which can be indistinguishable, have more subdued coloring, with rufous coloring on their lower backs and tails.

A female rufous hummingbird at a nectar feeder.By Ciar via Wikimedia
A female rufous hummingbird at a nectar feeder.

 

The females also have brown spots on their throats and, according to Cornell Lab’s All About Birds website, “usually” an iridescent reddish spot on center of throat. But from photos on the site and that I found elsewhere, this might be harder to see or even absent in some birds. Kate said she was behind the bird and didn’t have the best view of its throat, so wasn’t sure.

Checking her bird field guides, Kate wondered instead if the hummer could be a buff-bellied hummingbird. Not being familiar with this species, I posted a query on the Virginia Society of Ornithology’s va-bird Listserv to get input from experienced birders. The last time I did this was when I was for my Nov. 11, 2010, column, which was about a rufous sighting in Virginia’s Northern Neck, and the list members were very helpful.

I got responses by the next day that helped at least rule out the buff-bellied, with list members reporting that no buff-bellied hummingbird had (yet) been recorded north of North Carolina, and that was a rare sighting. A list member who had banded the buff-bellied on its known range, on the Gulf Coast, also pointed out that it has a red bill and is huge for a hummer — 4.25 inches long, with a 5.75 inch wingspan. In mentioning this to Kate, she said that, although she hadn’t noticed the color of her hummer’s bill, since it was mostly stuck in the verbena blossoms as the bird searched for nectar, the bird was about the size of the ruby-throated, which is 3.75 inches long with a 4.5 inch wingspan, also the same size as the rufous.

I checked the VSO’s official list for Virginia, which connects to data submitted to eBird, to see what other hummer species have been reported in Virginia. Other than the ruby-throated and rufous, there were five, all rarer than the rufous: Allen’s, magnificent, black-chinned, calliope and violet-crowned. In further discussion with Kate, she ruled out those rarer birds on the basis of their coloring.

Printed guides are the first resource I go to in trying to identify birds, although the range maps can go out of date quickly. “The Sibley Field Guide to Bird of Eastern North America” includes the rare birds, and has maps that tend to be more up to date than some other guides.

Guides with colored illustrations give a general idea of appearance of a typical bird in a species, often including both genders and subadults. While they leave room to imagine some variations, the guides that have photos usually only include one or two, which can actually see more “real” and limit consideration of variation. To get a better idea of the range of appearance, I usually also go to All About Birds, which, for each species, usually shows several photos, along with photos of similar species side by side. Last week, I visited Kate to look with her at photos of hummers on the site. We also talked about how the coloring on birds, especially hummers, can look different in different light.

So could the coloring on the side of the hummer she saw have been more a light rufous rather than buff? And could the bird have had few or even no spots on its throat, since her angle of view made that hard to see?

Several va-bird members offered to come and help ID the bird, and take photos, but alas, Kate hasn’t seen it again, so we’ll never know for sure. But she and I both agreed that the bird was most likely a female or immature rufous.

To have the best chance to see rare hummers here, leave out a nectar feeder all year. You never know who might show up.

© 2016 Pam Owen

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