| For the cowbird, it is an
unfortunate fact of life that human politics, ignorance and arrogance are almost always
bedfellows. Thats because not many humans
like cowbirds these days. It has become politically correct to blame the cowbird for an
impending avian disaster caused by human destruction of forests everywhere.
Somewhere, someone started bad-mouthing these most unusual of
our songbirds, and prejudice against cowbirds has broken light speed getting to the realm
of ignorance. For example, I recently heard a state forest biologist say "you ought
to shoot all the cowbirds you see."
Bad advice. Number one, killing any migratory songbird is a
violation of the U.S. Migratory Bird Act. Number two, the current human disdain for the
crafty cowbird is steeped in 1990 politics where only big time welfare recipients like
corporate farmers, major corporations and politicians are allowed to feed at the public
trough.
How could this tiny, unremarkable-looking
bird become the victim of our ever-vacillating climate of political correctness?
Thats an easy onecowbirds are not sugar farmers or industrial polluters, but
it is a parasite without a vote.
Cowbirds practice what is known at
"brood parasitism" and is an example of an "obligate parasite" because
it is locked into victimizing other birds which hatch and then raise its young. It is the
cowbirds only strategy, one it is "obliged" to use.
Cowbirds build no nest of their own and lay their eggs in at
least 200 different species nests instead. It is a North American variation on the
European cuckoos behaviorthe root word for the word "cuckold."
About 7 inches long, the brown-headed variety, so-named because
the males head is brown on a black body, is one of two cowbird species in North
America. The brown-headed is by far the most widespread, living in nearly every state. The
other is the bronzed cowbird, and it enters the U.S. infrequently in the southwestern
states. Three other cowbird species reside in South America.
According to the Encyclopedia of North American Birds,
the species got its name by associating with cows. In the Great Plains, they were called
"buffalo birds" because they hung around herds, picking up insects revealed by
bison movements.
Cowbird parasitism involves a lot
of scouting. Probably for this reason, cowbirds are among the early arrivals during spring
migration. Typically, the female watches a smaller bird build its nest. Then, usually in
early morning under dim light, she visits her victims nest when the nest-builder is
absent. The visit is made after a host bird lay eggs but before it has begun incubating
its own eggs.
The female cowbird lays her egg quickly and leaves, returning
later to destroy at least one of her hosts eggs by jabbing it with her beak and
flying away with it. She is able to distinguish between her own eggs and host eggs.
About half of all host species tolerate the cowbirds white
with brown speckled egg, incubate it and raise the cowbird nestling as if it were its own
offspring.
Since cowbird eggs hatch more quickly than most host eggs and
smaller birds are the most frequent targets, baby cowbirds are usually much larger than
the hosts own babies. When possible, the baby cowbird tosses at least one of the
hosts young out of the nest, thus ensuring it will get more food.
Some birds will not tolerate a
cowbird egg. The gray catbird and robin, for example, throw out cowbird eggs. Others bury
the cowbird egg and their own first egg or eggs by building another nest floor over the
eggs. Still other species, such as cardinals and yellow-breasted chats, simply desert
parasitized nests.
Birds most frequently parasitized by
cowbirds include all species that nest in open trees, bushes or on the ground.
Hole-nesting species like woodpeckers, chickadees and bluebirds are seldom victims.
While cowbirds are the only North American parasitic birds
"obliged" to parasitism as a way of life, there are many other species that
habitually lay their eggs in other birds nests.
Black-billed and yellow-billed cuckoos, grebes, rails, the
roadrunner, brown thrasher, starling, sparrows and some finches all victimize other birds.
The duck family has several members whose behavior approaches obligate parasitism--21
species are known for this behavior. The redhead and the ruddy duck are well known
parasites. Several pheasant species are parasitic, and both California and Bob White quail
lay in other ground-nesting birds nests.
Cowbirds have become a politically correct target of human
prejudice, not only because of their behavior, but also because of massive destruction of
forests. With more and more forest-dwelling species left without preferred nesting spots,
they nest in open places where they are vulnerable to cowbird parasitism. These migratory
forest-dwellers are among those whose numbers are crashing in the Americas, and the
cowbird has been labeled as one reason by some biologistsa claim championed by some
foresters.
It is at least ironic that foresters, those
"trees are crops" guys who love clear-cutting and pine plantations, have found a
7-inch bird to blame for part of the destruction they promote.
If there is a political lesson in
the cowbirds story, it is in the details of how any species becomes a parasite. One
favored theory among biologists is that parasitic birds developed their behavior after
they lost or while they were losing the typical avian drive to defend a territory.
Applied to humans, we label as parasites those who have no
territory, no property, to defend. In the case of the poor, the avian parasite example
suggests humans might be less parasitic if they had their own property to defend.
In the case of big corporations, their humans are so distant
from the land that they have abandoned defending it and now concentrate on raping it
instead. Taking their territory away or requiring them to live amidst their own filth and
destruction might remove the worst welfare abusers from Americas roll of parasites
instead of the lonely cowbird, the latest victim in the continuing legacy of Reaganism and
1990s political incorrectness.
12/2/97
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