Twenty-five years ago I assisted Arlo Raim who was
radio-tracking female cowbirds during the nesting season
in eastern Illinois. He came up with a few interesting
conclusions:

Cowbirds occupy a home range and a male-female
pair hang out together. That doesn't mean that a
female isn't courted by other males, but she does
have a male to which she is bonded. The female lays
her eggs in nests within this home range, a single
egg a day right at daybreak.

However, the home range is not a foraging area. Later
in the day, after egg laying, males and females gather
into flocks and move out into more open country to feed.

So as far as limited resources (potential host nests) are
concerned, cowbirds are somewhat territorial. However, I
don't recall what other behavior Arlo recorded, which
would better answer Michael's question.

--Jerry <tangren at wsu.edu>
Wenatchee WA

-----Original Message-----
From: TWEETERS-owner at u.washington.edu
[mailto:TWEETERS-owner at u.washington.edu]On Behalf Of Michael Price
Sent: Sunday, July 12, 1998 1:25 AM
To: tweeters at u.washington.edu
Subject: Re: Cowbird Studies


Hi Tweets

Just to pass on that while we think of Brown-headed Cowbirds Molothrus ater
as being non-territorial, there's a male across the road disproving the
assumption.

At least three weeks ago, I began hearing a strange call across the street,
a thin. clear version of Western Wood-Pewee Contopus sordidulus, which after
several days I finally narrowed down to a male cowbird calling from the top
of a pine-tree of some sort in the yard directly across the street. Three
weeks later, he's still out there every morning, afternoon and sometimes
evening still, calling from the same perch atop the same tree.

So. Do females show the same territoriality? Is the male calling to collect
the fledged cowbird young? Why is he still calling?

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery, and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)