| 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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