Sounds of Spring

[Shawn & Paul Jacobsen]

I walk at Bald Hill (Corvallis) most days.  This past week it seems like I am hearing more of what I would call Spring bird singing.  I've noticed Red-Winged Blackbirds, but also a couple of different sparrow species (I really need to learn to identify birds by sound), much more than I had been hearing.

Is this just wishful thinking on my part or have others noticed this same increase in birds announcing their presence or claiming territory or just feeling good?

Paul

Corvallis

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[Lisa Millbank]

You're right about the increased singing lately, even though most birds won't be nesting for 2-3 months. There are certain male songbirds whose songs are heard occasionally through the winter, but others hardly do it at all, or only give fragments of song.  Some of these males actually lose the ability to sing because of a lack of sex hormones during the non-breeding season.  There are certain regions of the brain that actually shrivel up when the male has low levels of androgens. Increasing day length triggers a gradual rise in sex hormone production in both sexes, and for males, their shriveled singing regions in their brains re-grow and they begin to sing more.  Some females do sing, especially in non-songbirds, but among temperate climate songbirds it's largely a male behavior.

Some of the early singers include Lesser Goldfinches, American Robins, Song Sparrows, Bewick's Wrens, Black-capped Chickadees and Purple and House Finches.  As mostly resident birds, they may be maintaining some control over feeding territories, bonding with their mates, or establishing some kind of rank among the other males.  Although, when the sun comes out, they probably also just feel an urge to sing rather than really consciously thinking about all of these things.  A lot of times you'll hear males of many species singing during migration, when they don't actually have a mate or a territory.  I assume that once their hormones are at a high enough level, migrating males just feel the urge to sing daily even if it's not accomplishing much, but once they get to their destination the singing becomes more purposeful.  I think that in general, males probably do enjoy singing, but it is certainly not always in a "happy" context.  Two males may use singing to try to one-up each other, and if that doesn't work they may fight quite violently, with the winner popping up to sing vigorously while the loser slinks away quietly.

Lisa Millbank

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