Here it is: see what you
think!
I called Art Clark, vertebrate zoology curator at the Buffalo Museum of Science. This was unusual for him as well. He and I both searched the literature but found little help there.
The four of us -- Art, Mike, Noreen and I -- came up with possible causes of this aberration. Unfortunately, each had shortcomings.
(1) Something wrong in the molting process. John Terres in "The Encyclopedia of North American Birds" points out that molts usually replace feathers in waves so that bare spots rarely appear. This process might have malfunctioned. But many birds at once?
(2) Disease. We found none with this characteristic.
(3) Feather mites. Why then are only the heads affected?
(4) Feather-picking. Some birds, especially crows, peck head feathers from others. But they usually attack their own species.
(5) A feeder entrance rubbing off head feathers. None was found nearby.
Until recently, that is where the matter would have ended. However, today we have an effective new resource -- the Internet. I posted a description of our dilemma together with a request for assistance on the Internet mail group, Birdchat. Through this medium my message was carried immediately to 1300 ornithologists around the world.
Among the many responses, most told of personal experiences with this phenomenon. For example, Julie Stielstra of Illinois wrote, "This time every year this comes up. I've been laughing at a totally bald blue jay, a mutant-punk grackle with a Mohawk and a very pathetic looking cardinal with a little plume on a bald head at my feeder." (Note the remarkable coincidence of her species with those reported to the Oleks.)
But two respondents gave us our answer. Mark Monroe, biologist at Hawk Mountain Sanctuary in Pennsylvania, wrote that it was indeed a mite infection and that it would not affect the next molt. And Susan Thuener -- quite appropriately of Mohawk, New York -- wrote, "The head is the one vulnerable spot on the bird that it cannot reach to preen."
And so our mystery is solved. Seasonally, a few birds are attacked by feather mites, tiny arthropods whose feeding destroys feather shafts. Normally, the birds would divest themselves of these mites by preening, but birds cannot effectively preen their own heads. Once the mites have destroyed their food source on the birds' heads, they must either move on to a new victim or place themselves in jeopardy on another area of their host's body.
We close our file on The Case of the Bald Birds.
Credit for the photograph of the bald cardinal goes to Marguarite McGinnis of Buffalo
who took the picture in Batavia, Illinois.
My column needs to tell a brief story and reach a kind
of closure so I
left the matter resolved, but there is clearly more to the story. In
particular, not everyone agrees with this assessment -- what else is new?
-- and I offer here some comments by other observers. (Not all of the many
informative messages I received are posted and some are posted only in
part. I apologize to all who may feel that I have done violence to their
views. If you feel especially put upon, please contact me and I will edit
your message.)
Sherry Goldsmith, Los Angeles, CA: I don't think it is
necessarily an
either/or situation - either all bald birds are molting or all bald birds
have mite or nutritional problems. Some birds may be bald because they are
molting, others birds may be bald because they have mites or nutritional
deficiencies, and yet other birds may be bald because of a combination of
conditions.
An example, I believe, is a scrub jay I was friends
with for several
years
when I worked in the concrete canyons of the high-rise Century City area
of Los Angeles. I called him Scruffy because, well, that was what he was -
almost totally bald on his head and neck and totally bedraggled feathers
elsewhere. He was also rather listless and "depressed" for a scrub jay,
sitting huddled on a branch for long periods of time. He looked and acted
like that for the first several months I knew him (I met him in about July
or August), until I finally stopped at a pet store one day and got the
best, most complete avian supplement I could find, then got some mealworms
from a fishing tackle shop. Each day I gave him several mealworms to which
I had added a drop of the supplement. Within a week or two he started to
make a dramatic improvement and after about a month had become a
beautifully sleek and energetic scrub jay. I continued to offer him
mealworms and raw pinon nuts, all of which he eagerly accepted, and he
went on to acquire a mate the next spring and successfully nest twice
without ever again displaying any feather problem.
This of course is purely anecdotal evidence, but I'm
convinced that in
Scruff's case, the poor feathering was basically due to dietary
deficiencies - in his very marginal urban environs, I suspect he was
reduced to scavenging too much people junk food from the local fast food
outlets.
Matt Fain, Carbondale, IL: Only in the past couple of
years have I been
noticing such extensive feather loss in cardinals as well. I am familiar
with the usual scruffy look during molt. I am not convinced that this
phenomenon is entirely due to molt, although the condition may be made
even more noticeable in the fall because of it. I don't think they're
mutually exclusive possibilities. [speculation mode: on] Birds with
heavier parasite load could turn "balder" than their not-so-infested
neighbors during molt. [speculation mode: off]
I have a pair of cardinals in the yard this summer that
both have this
condition. The male has been bald since April; the female since sometime
in May. That's months! So I also would like to know more about what is
going on.
Liz Day, Indianapolis, IN: The female cardinal that I
saw became
progressively balder over the course of a few months; by breeding season,
her head was completely featherless. There must be more than one kind of
baldness going on.
Lyn Atherton, Tierra Verde, FL: I have never seen a
completely "bald"
wild
bird whose baldness wasn't related to its post-breeding molt, but I'm not
insinuating that it couldn't possibly happen for other reasons. Perhaps
the "baldness" is seen more often in individuals breeding in hotter
climates. An unusually hot breeding season in a normally cooler climate
may cause some individuals in that area to become bald during that
particular season.
Losing head feathers during the post-nuptial molt is a
normal process
in
some species including cardinals, Blue Jays and Common Grackles. The fact
that a vet gave medicine for this condition because he thought the cause
was mites and dry skin indicates he needed to take a basic ornithology
course! After a week or so the bird would have had a "normal appearance"
even without medication. (Hope the office visit and medication weren't too
expensive!)
Art and Hanna Richard, Ingram, TX: As a bird bander I have captured
many Cardinals
and
Blue Jays with severe head molt. I took every one of those birds, held
them over a white tissue, rubbed their heads, and examined the tiny matter
that fell to the tissue with a hand lens. I, personally, have never found
feather mites in the head area but did find tiny particles of quills. For
some reason, all the feather mites I have found were on the body and/or
wing feathers.
Liz Day, Indianapolis, IN: Wow. That's persistence!
Perhaps the mites
left
the head after the feathers were all gone and moved to the neck?
Carolyn Hall, Bassett, NE: Gerry, a friend here in Nebraska found a
wren attacking a
nest of almost grown baby eastern bluebirds. One baby had a totally bald
head after the attack. I haven't heard if they have seen it since it
fledged. They moved the bluebird nest box about 100 yards further away
from the trees and weren't certain that the adults would find the box, but
before they were through re-erecting the box the parents were there
scolding them and immediately resumed feeding as soon as the box was up.
Miracles can happen.
Laura Erickson, Duluth, MN: I have done quite a bit of
rehab for
several
years, and kept a Blue Jay as an education bird for 8 years. She molted
all her head feathers simultaneously every year and was bald for a couple
of weeks each time, looking awful. Meanwhile, a second Blue Jay I had to
keep for several years molted his head feathers a few at a time, so he
never looked awful. I never understood why Sneakers molted one way and BJ
another.
Mort Cooper, Miami, FL: We here in South Florida are
now into our
annual
fall molt. The Boat-tailed Grackles become tailless and our Blue Jays are
entering their 'vulturine' stage where they lose every feather on their
heads at the same time and fly around like diminutive blue vultures. It
takes about 10 days for each individual to recover complete tail or head
plumage.
Gail Petri, Fairport, NY: We have had a bald
cardinal visiting our yard and he has
been totally bald all summer. No sign of new growth -- but otherwise very
healthy and active. I
watched the same bird feast on a hatch of some sort of ant-like insect
right next to our house. He stayed in the same spot for about 20
minutes, and after eating each insect, he twisted his head toward his
tail and seemed to scratch his beak on his tail feathers. It was a very
unusual behavior - and hard to describe in words. Have you ever heard of
anything like that. What was it doing? Another mystery yet to solve.
Response: This is almost certainly behavior technically called anting.
Birds obtain acid from insects and rub it into their feathers and skin in
the process of grooming. Ants are most commonly used for, I believe, their
formic acid (ants belonging to the family Formicidae). This may offer some
additional support to the possibility of mites.
Two still more recent columns on this topic have appeared: Bill Hilton's and Ben Burtt's.
Well, not quite.