Thursday, July 25, 2013

survival of the fittest

Brown-headed cowbird photo by Rex McDaniel.

Behold! One of the fittest species I know. 

OK. This is one we love to hate, but if fecundity (From the Latin fēcunditās meaning fruitfulness) is the measure of a successful species, if survival of the fittest is about successfully producing the most young thus passing on the most genetic material—your unique genetic blueprint—then brown-headed cowbirds have it figured out.

They're resourceful parents. When it comes to parenting, they are no-shows. As parents go, they truly go. No cowbird ever builds a nest or raises its own babies. They don’t even know how. 

They’re clueless parents, so they let some other bird do the nest building and incubating and nurturing. No male brown-headed cowbird ever gets a Father's Day card; no female a Mother's Day card. They do not deserve it.

Each spring, mated female cowbirds slip around the neighborhood, laying their eggs in other bird’s nests. And because they don’t have to do the work, a female cowbird may lay up to 40 eggs over the course of several weeks. 

The sneaky mother may also remove one of the natural eggs from the nest so that the host mother does not notice the subterfuge. Over 100 different species of birds have been known to raise cowbird babies. And in many cases, the foster parents are smaller and probably exhausted by the time the nesting season is over.

Cowbirds are native to North America. As a species they have a good survival strategy, but as parents they're eye-rollingly skanky, letting someone else raise your offspring. What personal satisfaction do you glean from it?

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