Sex and real estate

We are still about a few days away from the vernal equinox, but it is impossible to mistake the signs of spring:  Trees are blooming (gesundheit!), bees are buzzing, and birds are singing. In our canyon, the California quail have disbanded their large winter covey and are foraging in male-female pairs. In the past few weeks I've watched and listened to red-shouldered hawks claiming their territory. All that I'm waiting for is the return of the downy woodpeckers drumming on the utility poles and the arrival of mud-carrying swallows at the marine lab to know that spring has truly sprung.

One of my favorite spring sights--and sounds!--is the red-winged blackbird (Agelaius phoeniceus). They are in California year-round, but their raucous mating displays make them much more visible in springtime.

Male red-winged blackbird in display posture
Male red-winged blackbird in display posture

Male red-wingeds are a glossy black with puffy red epaulettes, which they flash as they are calling. This time of year it is common to see a bird perched on the end of a twig, showing off his shoulders and his loud, clear voice.

Here's what it sounds like: Call of red-winged blackbird

The conspicuous markings and piercing call serve to advertise a male's territorial claim. He states very emphatically, "This is my patch of rushes, so BACK OFF, DUDES!"  If he is successful in holding off interlopers, a male may mate with several females within his territory. This is a Good Thing, no? Females benefit from this arrangement because a male who can stake out and defend a territory is presumably vigorous and will pass those healthy alleles to his offspring. So it's a win-win situation and the best possible baby blackbirds are produced every generation.

Sexual selection in action!  Gotta love it!

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