Tuesday, June 1, 2010
Ball 5. Old Blue Eggs
Trolling through the abstracts of an ornithology meeting held a few months ago, I came across the following study: Robin's Egg Blue: Is Egg Color a Sexual Signal?
The authors, from Canada, didn't want to talk about their findings (a paper in the works, jeopardizing publication, etc., etc.), but it seemed like too nifty a story to let drop. Therefore:
The blue of the robin's egg is among the most vibrant colors in nature. In
fact, it's so striking that researchers have long puzzled over why evolution
would so obviously advertise robin’s eggs to potential predators.
Canadian ornithologists say they have an explanation. They found that male robins spent more time feeding their chicks that hatched from the most vividly colored eggs. That suggests that robin's egg blue is a signal to males about the fitness of their mates and the offspring they've
produced, according to the researchers.
A confession about eggs: As a birder, it pains me to think of even "trash" species suffering—particularly at my own hands. But the other night my wife and I were forced to clear a pair of vociferous house sparrows from their long-time home underneath a broken AC unit in one of our windows. Their noisy ways, and the dust from their grassy nest, had finally shattered whatever pretense of live-and-let-live we'd kept up for the children.
When we removed the behemoth machine, which was at least 30 years old and must have weighed 120 pounds, we found a clutch of seven, warm eggs in the nest. The parents, having been scared away by the commotion, were nowhere to be seen.
The next morning, the female sparrow was perched on the sill, chirping what at the time seemed like a confused and desperate question that nearly broke my heart. Until the morning after, when, at about 4:45, she was back to her usual, grating ways. In fact, she seemed louder than usual, with an insistence that I took to be hectoring of her mate for his poor choice of an apartment. So, the early bird may get the worm, but the earlier bird gets evicted.