Brown-headed Cowbird: Clever or Conniving?

Brown-headed Cowbird at my feeder.

Brown-headed cowbirds are not as stunning as red-winged blackbirds nor are they as gregarious as crows and ravens, but they definitely have their own unique and fascinating story.  First of all, their name.  Cowbird?  No, they do not look or sound like a cow, neither do they steal droplets of milk from the udders of cows for their young, as one myth declared.  It's believed they were given this name long ago when they used to follow herds of bison.  Insects were their primary diet, followed by seeds and grains, and where the buffalo roam--or herds of cows for that matter--there are insects.  And so their name, which is, after all, much easier to remember than Molothrus ater. 

While we see many varieties of blackbirds in our yard, this particular male bird stands out for two reasons.  One, its distinct brown head and black body, and two, because it's usually the only one of its kind in the crowd.  While they sometimes travel in small groups, I've only seen one at a time at my feeder.

Females, as always, are plain gray-brown and can easily be mistaken for other types of female blackbirds.  But male cowbirds have this distinct brown-head.  You can't miss them.  However, while the male caught my attention, which led me to look them up, it was what I learned about the plain gray-brown female that held me spell-bound and made me a fan.

Consider: If this plain little bird was supposed to keep up with the traveling bison herd, how was she supposed to build a nest, lay and incubate her eggs, and then feed and raise them?  Try as we women do, we can't do it all.  So this clever little bird spots a well-made nest where at least one other egg has been laid by some other bird, and when that bird darts off for a bite to eat, Mama Cowbird lays one of her eggs in that bird's nest and goes on her way.  The unsuspecting foster mother bird returns to her nest, incubates "her eggs," and feeds them all when they hatch, even the odd looking hatchling.

Meanwhile, Mama Cowbird continues her stork-like delivery from nest to nest, laying anywhere from 10-40 eggs per year.  While this is generally very successful, there is one potential problem involving the nests of House Finches.  Since finches feed their young primarily seeds and grains, baby cowbirds may not survive without an early diet of insects.  Perhaps this is why the cowbird lays her eggs in so many different nests, increasing their chances of survival.

Cowbird egg in a Robin's nest

In the bird world, they are considered "brood parasites" and in some cases "nuisance birds" because the eggs and young of other birds are sometimes destroyed in the process, but I find this little bird fascinating, for she's found a way to survive in a bustling, fast-paced world.

Post script:  Just came across a fascinating study on how cowbirds learn to be cowbirds.  If they are raised by a different bird type that builds nests and tends to young, wouldn't a cowbird learn to do the same?  Nope.  Not only is it in its nature to be a cowbird, but a study showed that they actually sneak out at sundown and find where cowbirds roost and hang with them at night, then sneak back to their nests!  In addition, there are studies that have found that the mother doesn't entirely abandon her young, but somehow keeps tabs on them, checking in and even evaluating which nests were better than others.

 https://www.audubon.org/news/how-does-cowbird-learn-be-cowbird

Further Reading
https://www.allaboutbirds.org/guide/Brown-headed_Cowbird/id
https://www.audubon.org/field-guide/bird/brown-headed-cowbird
https://nestwatch.org/learn/general-bird-nest-info/brown-headed-cowbirds/