Wednesday, March 19, 2014

A Little Too Aggressive

I have observed for some years, in late winter, a pattern of aggressive behavior by Yellow Rumped Warblers.  The previously inoffensive birds take on a role of feeder cop, chasing off other species at every feeder they can cover.  I'm a little embarrassed to say that I think I finally figured it out.  Perhaps I was fooled that the birds eventually migrate northwards.  But it strikes me they are responding to hormonal changes and compelled to defend a territory.  Even if it's a temporary one.  The nature of the territory may have to do in large part with food supply---no doubt the warblers need to build up an energy stock before committing to the migration.  But even still, other migrants don't do this in winter here.  The warblers are simply more wired.  I take this as a sign that they will ship out within the next few weeks and leave our feeders in peace.  And this will be welcomed.  Right now they are simply too aggressive!

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