June 19, 2013
Written by Jack Sanders
Thursday, 13 January 2011 12:14
“Clothes make the man,” wrote Mark Twain. “Naked people have little or no influence in society.”
The same is even truer of birds, for the color and design of a coat of feathers can serve several purposes essential to survival. Sometimes, however, both color and design can confuse us, as it did with two birds spotted in the past week by readers.Color and design help tell one bird that another is of the same species. In many birds, such as goldfinches and cardinals, color and design distinguish male from female, and the quality of the plumage can help attract the opposite sex.
In many species, color and design camouflage a bird, making it difficult for its enemies to see. Birds that nest on the ground often blend in with their environments. Rails, for instance, look like the reeds they live in. A Brown Creeper is virtually invisible on the side of a tree, at least until it moves, and even then, it’s hard to see. The ladder-back design on a woodpecker, which may seem flashy when the bird is hanging from a suet feeder, blends in well with the bark of a tree.
Still other birds may use color to help them keep warm. The black feathers of crows and ravens, for instance, are better at absorbing the heat of the sun in winter than are lighter-colored feathers.
Scientists are still discovering reasons for particular colorations in bird feathers. For instance, in 2005, Dr. Alberto Palleroni of Harvard published a study in which he found that a white patch on the rump of many wild pigeons helped protect them from attack by Peregrine Falcons. Falcons kill by approaching and hitting the victim from the rear at a high speed — like a punch in the sky. In chasing down the pigeon at speeds of up to 200 mph, the falcon tends to focus on the white patch, and doesn’t immediately notice when the pigeon changes its wing movement to veer off — like a jet rolling out of formation — to avoid being hit by its pursuer. The patch distracts or tricks the falcon.
Pigments produce the color in a bird’s feathers. Most birds use only one or two pigments: melanin, which produces black, brown, and gray shades, and carotenoid, which produce red and yellow tones. Sometimes the pigment production goes awry.
“I have had this sparrow feeding in my yard recently along many other white-throats,” writes Chris Correale of New Canaan, who sent the accompanying photos. “He is sporting ‘white cheeks’ along with his white throat. I am guessing he is a White-throated Sparrow with a little extra ‘flair!”
That’s a great way of expressing what’s happened here. This is probably a White-throated Sparrow with a touch of leucism. Leucistic creatures lack pigment in part or all of the surface of their bodies, which, in birds, is reflected in the feathers. It’s a genetic aberration.
Sandi Lincoln of Wilton sent us photos of a bird she calls “Pinky” that has more red on it that you would expect from a typical House Finch or Purple Finch. We could not tell which species it might have been because the pictures weren’t sharp enough, but since these finches are somewhat variable in their feather pigmentation, it’s probably an example of a finch whose carotenoid went a little overboard.
Family-friendly Bird Count, ‘Project FeederWatch’ Saturday, Jan. 15, 1 to 2:30 p.m., Greenwich Audubon, 613 Riversville Road, RSVP 203-869-5272 x221, greenwich.audubon.org.
Bird Seed Sale, Saw Mill River Audubon, Saturday, January 15, 9:30 a.m. — 12:30 p.m. Pruyn Sanctuary Office Entrance, 275 Millwood Rd, Chappaqua, www.sawmillriveraudubon.org.
‘EagleFest’ on the Hudson River, eagle watching with warming tents, exhibits, live eagle programs, Saturday, Feb. 5, 9 to 4, Croton Point Park, (914) 762-2912 or www.teatown.org.
“First Sundays,” bird walks open to all ages and skills, at Greenwich Point, with Meredith Sampson, first Sunday of the month, through May, 9 a.m. sponsored by Wild Wings, Inc., Bruce Museum and Audubon Greenwich, 203-637-9822.
Copyright 2010 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] yahoo.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877; or call 203-438-1183, extension BIRD (2473), and leave a message with your report, spelling your first and last names and telling us your town. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.
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