Crazy Bird Bills

Imagine a Hairy Woodpecker with the beak of an American Woodcock. That’s the photograph that greeted me when I opened an email last week from my friend and ultra-observant naturalist Jo-Ann Ecker. The freak woodpecker has been visiting her suet feeder and despite a wild bill, appeared to be healthy.

Scattered reports of bill deformities are to be expected, but a sudden and large outbreak in a region can be a sign of a much larger ecological problem. In the 1970s there were high rates of crossed beaks and other malformities in Great Lakes waterbirds, later linked to organochlorine contaminants. In the 1980s agricultural runoff that contained high levels of selenium was implicated in nestling beak deformities in southern California.

Odd bills are usually quite rare for songbirds. I have capture, banded and released thousands of songbirds over the years and I can only recall handling one bird with a deformed bill. After banding a Gray Catbird with a grossly crossed bill in 1993 at the Rogue River Bird Observatory in Michigan, Julie Craves, an ornithologist and fellow Audubon Guides blogger, examined published rates for songbirds and found them to be variable but generally low.

Recently, ornithologists in Alaska have documented an unprecedented number of bill deformities around the state, which has extended southward along the Pacific coast into Washington.

“The prevalence of these strange deformities is more than 10 times what is normally expected in a wild bird population,” said research biologist Colleen Handel to the Associated Press.

Handel and her colleagues recently published an article in the American Ornithologists’ Union journal, The Auk, which described their findings. Over the last decade they documented 2,160 Black-capped Chickadees and 435 individuals of 29 other species of birds with grossly overgrown and often crossed beaks. They found very few incidents of nestlings with abnormal bills suggesting it mostly occurred later in life.

A bird’s beak consists of bone overlaid by keratin, the same protein that makes up hair, feathers, claws and fingernails. The keratin constantly grows and wears away just like your fingernails. But these birds have keratin growth that is about two times faster than normal.

The exact cause remains a mystery. Possible causes include nutrient deficiencies, disease or parasites, trauma, genetic abnormalities, or contaminants. Scientists are looking at all of these, but the evidence thus far seems to point to contaminants as a likely culprit, perhaps combined with some other disorder.

Meanwhile, like my friend Jo-Ann, you can help scientists unravel this mystery. Keep a close eye on the birds visiting your feeders this winter and if you see any with even a slight abnormal beak, try to get a photograph of it and report it to the Alaska Science Center.

Tags: beaks, bill deformities, bills, birding, birds, deformities, MI, nature, ornithology, VT, wildlife, Woodpecker

This entry was posted on Tuesday, January 17th, 2012 at 9:20 am and is filed under Entires by Kent McFarland. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.