Cowbirds are despicable. I would like to put this in better terms, but
despicable is the only term of appropriate strength.
In more sciency (my own
term) language, cowbirds are something called “brood parasites.” This means that mature cowbirds lay their
eggs in the nests of other bird species and then allow the other birds to hatch
and raise their young.
Cowbirds are not
particularly fussy about who raises their young. Any songbird species will do. The host birds will sometimes raise the
cowbirds at the expense of their own brood.
Cowbirds are often conspicuous, if not grotesque, in comparison to the
birds raising them. Posted is a photograph (thanks to Audubon) showing a tiny
warbler feeding a gigantic cowbird.
According to Matt Soniak, as found in his online article at www.audubon.com
titled How Does a Cowbird Learn To Be a
Cowbird?, the most interesting point in all of this is that a cowbird
remains a cowbird, even after being raised by another species.
That really is something.
You might think a cowbird
raised as a chickadee would assume the habits of a chickadee, but this does not
happen. Consider how humans exposed to
the same conditions of upbringing might respond. An identity crisis might result. A certain segment of humans enduring such upbringing
would require extensive therapy to (pun intended) fly right.
Recent research has
discovered part of what helps a cowbird learn to be a cowbird. Juvenile cowbirds—ever despicable as their
parents—sneak out of the host family natal territory (nesting area) at sundown
to roost in open fields. There, they find other cowbirds to hang with during
the night. Probably, this is a rough
equivalent to our rowdy teenagers joining a gang. In the morning they return for breakfast with their
foster family. Eventually, the birds
abandon the family that raised them and do only cowbird things.
Additional research
revealed that, to some degree, adult cowbirds monitor their young in the nests
of the birds raising them. The success
or failure of certain host species may impact the choice of future nests. One researcher, Mark Hauber, contends that
the adults may even initiate limited contact with their young. They may try to make certain cowbirds become cowbirds.
Posted below is a
photograph of an adult cowbird.
--Mitchell
Hegman
Interesting. So what makes cowbirds despicable?
ReplyDeleteThe fact that the leave their young in the care of host birds that often sacrifice their own young to care for the cowbirds is despicable. I know..nature is nature. Despicable is a human construct.
ReplyDelete