Wingnut
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We have a small platform feeder that hangs in front of our deck windows (close enough to discourage flight toward the glass). It’s popular with the resident cardinals and the red-winged blackbirds recently returned from winter quarters.

Cardinals feed one at a time. They do not share. Cardinals have nesting territories that can range from half to six acres. Male cardinals defend those lines.

The blackbirds are quite willing to share the feeder, often three or four of them up there at a time. The blackbirds also are colonial nesters, females building their marsh nests in loose groupings. While the males compete for territories, these birds obviously don’t mind company.

So, is feeder behavior a reflection of nesting behavior?