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May 2010 cover image 12 Vulnerable Nursery

When Birds Go Bald

That cardinal or blue jay without head feathers may just be molting.

By Sheryl Smith-Rodgers

Yikes! Ugly doesn’t even begin to describe the skin-headed bird that raided our sunflower feeder last summer. Bright blue plumage everyplace else and a characteristic cocky attitude confirmed the obvious: We had a bald blue jay in the neighborhood.

I didn’t worry too much. But lots of people do. So much that they phone local wildlife officials, asking for someone to come and rescue the “sick” birds they see in their yards. Most callers describe male northern cardinals; others report blue jays and common grackles. No matter the species, they all share the same vulturine head — dark-skinned, featherless and downright ugly.

Photo by Kathy Adams Clark

What’s up? No one knows for sure, but experts offer several explanations. At the Cornell Lab of Ornithology, researchers with Project FeederWatch — a winter survey of birds at North American feeders — point to different molting patterns as one reason.

First, some basic avian biology: Because feathers wear out, birds molt old ones once or twice a year, usually in late summer and early fall, and grow new replacements. Normally, the process occurs in stages so birds can still fly and remain healthy.

Sometimes, though, a cardinal or blue jay may molt its head feathers all at once instead of gradually. Granted, the poor bird may look diseased, but the ghastly condition is only temporary, and harmless as well. Head feathers usually grow back within a few weeks.

Other reasons? Some bird watchers theorize that malnutrition or other environmental factors could lead to bird baldness. In other cases, birds may lose head feathers because of an infestation of lice or mites.

“I don’t buy the mites thing,” says David Bonter with Project FeederWatch. “Birds molt at different times and in different ways. There are some general patterns in terms of which feathers are replaced at which time of the year and in which order. In reality, however, there’s an incredible amount of variability in molt patterns, even within the same sex or age class of birds within a species at the same time of the year.”

Two blue jays kept by a former wildlife rehabilitator in Duluth, Minn., during the 1990s best confirm Bonter’s assertions.

“I was rehabbing one bird, and the other one was a licensed education bird,” recalls Laura Erickson, now the science editor with the Cornell Lab of Ornithology. “They were in adjacent cages. Every fall for eight years, my licensed blue jay molted all her head feathers simultaneously. The other one didn’t.

“So it seems that some individuals molt their head feathers more quickly than others,” adds Erickson, who has authored four books on birds. “Which can lead to a very embarrassing appearance for a week or two until the new feathers grow in. It’s a good thing birds don’t have mirrors!”

On a positive note, bald birds make a great educational tool.

“Since the cardinal is such a visible backyard favorite, people get a peek at a world of bird physiology that they’d normally not witness,” says Cliff Shackelford, an ornithologist with the Texas Parks and Wildlife Department. “At first, most observers worry that the sky is falling when they see a bald cardinal at their feeder. But once they do a little homework, they find out that the bird is molting, which is normal. The next step is to keep observing, keep asking questions and keep learning!”

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