Brown Headed Cowbirds

We have thousands of these, most raised by Red Winged Blackbirds.

so glad that is what they are preditorizing. Really hate it when they get into warbler nest

Why are they raised by the RW Blackbirds?

Cowbirds are 'brood parasites'. They lay their eggs in other species nests.

http://www.audubon.org/bird/research/#introduction

That's what I was thinking they might be doing. So do they actually destroy the other birds eggs?

Yes. We have seen very few Redwings this year.

Oh, that's terrible. I have very few birds that come to my yard because we are in a new development with no big trees. The first bird we saw, other than doves and sparrows, was a RWB. I was so excited! We've seen one or two a year for the last few years and I've even learned to know their call. :)

Just a few excerpts from the [Audubon link] provided above by claypa:

"Host species often renest and are able to make-up reproductive success lost to parasitism. Contrary to previous notions, there is often little net loss in host reproductive success over an entire breeding season."

"Scientists suggest there is little evidence that cowbirds have population-level impacts on hosts."

"Scientists advocate protection and restoration of host breeding habitat, and improvements in grazing and agricultural practices."

:D

But there are exceptions. I don't like them much, but I leave them alone.

This message was edited Jan 6, 2007 5:37 PM

It is a kind of grim scenario, but if it's any consolation, these birds' population is in decline