Friday, March 12, 2010
Not so ordinary!
This Song Sparrow will never concern itself with giving half-hearted attempts belting out his melodious arrangement of notes and phrases. How fortunate for him! Though nature provides ample material to write about, my inspiration can often be elusive. After blogging for so long, sometimes I feel like I keep telling the same stories over and over, so I probably wouldn't make a good Song Sparrow. Before getting ready for work this morning, I realized it was warm enough to open my apartment windows. Almost immediately, I heard my first Song Sparrow of the year. Inspecting the courtyard with my binoculars, I counted three of them foraging on the grass where there was snow just a few days ago. All three birds were taking turns singing and might be, perhaps, part of a community of Song Sparrows of the courtyard. I enjoyed believing that, anyway. After reading Donald Kroodsma's book, The Singing Life of Birds, I'm not nearly as dismissive of these common little brown jobs as I was over a decade ago.
What sounds to us like the same series of notes repeated over and over is quite a bit more complex than we're able to discern without special recording equipment. A truly fascinating thing I've learned about Song Sparrows is their ability to use songs for both type matching and repertoire matching with neighboring brethren. A Song Sparrow has a choice when responding to another male's song. If he knows his neighbor's song, he might respond by singing it back (type match), but he might also come back with a different song the two birds also share in common (repertoire match). By using sonograms and playing back songs, it's been discovered that early in the breeding season, as males are establishing territories and trying to attract a mate, they mostly type match songs with one another. But as the breeding season progresses males are more likely to engage in repertoire song matching. What's especially interesting is the particular shared song chosen signals the level of aggression towards a neighbor, the greatest threat being a type match. Established neighbors always respond with a shared song, but if a stranger enters the neighborhood and tries to swipe territory or steal a mate, sparrows of the "community" sing or respond to the invader with songs that are not shared with their neighbors. This can confuse the intruder and often results in him being chased out of the community!
Pretty cool, huh?
Song Sparrow © 2010 Mike McDowell
Posted by Mike McDowell at 8:20 PM