Posts Tagged ‘Ornithology’

Male blackbirds intent on protecting turf: Bicyclists, pedestrians report attacks; experts blaming feisty males

June 23, 2008

There’s a predator lurking in Chicago-area bushes these days. He strikes from behind, when victims are least aware. And the worst part, says ornithologist Doug Stotz: He could be almost anywhere.

Nesting season is in full swing for the red-winged blackbird, making the males extremely aggressive. Walk or bike too close to one’s nest and expect to hear its high, menacing squawk overhead. Then comes the peck-peck-peck on your head, victims say, or claws rustling your hair.

It happened to Holly Grosso. The businesswoman was on her cell phone, walking along West Grand Avenue near Rockwell Street on Wednesday, when the bird—dubbed “Hitchcock” by area workers—made its move.

“Something just came down, pecked me in the head, took my hair and started flying away,” she said. “It’s so bizarre. It’s this little bird.”

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Marriage Crises In Blue Tits Are Probably Caused By Other Females

May 26, 2008

Divorce is widespread, not only in humans, but also in socially monogamous birds like the blue tit. Behavioural ecologists Mihai Valcu and Bart Kempenaers from the Max Planck Institute for Ornithology in Seewiesen found divorce rates of up to 50% in a long-term study of this species. But why do partners split up? To answer this question, it helps to know who suffers and who benefits from the separation.

Previous studies on small passerine birds, such as blue tits, have shown that females do better after divorce. This is because they had more offspring with a new partner. “These findings have led to the suggestion that the females should take the initiative to leave their partner”, says Bart Kempenaers, Director of the Department Behavioural Ecology and Evolutionary Genetics at the Max Planck Institute for Ornithology in Seewiesen.

In their study however, Kempenaers and his colleague Mihai Valcu obtained evidence that the increased reproductive success of divorced females may not be caused by getting a better partner, but by leaving the previous home and moving to a better place. Such breeding dispersal is common in females, in contrast to males, who rarely leave their territory after a divorce.

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British Birds Adapt to Changing Climate

May 9, 2008

Climate change threatens many animals — but with any luck, some will handle weather shifts with as much aplomb as Parus major, a colorful songbird also known as the great tit.

In a study published today in Science, ornithologists from the University of Oxford tracked the egg-laying times of great tits in Wytham, England. Since the mid-1970s, temperatures in Wytham have risen steadily, hastening the start of spring by two weeks. The birds have followed suit, timing their breeding to coincide with earlier hatches of their favorite food source, a species of moth caterpillar.

The birds’ adaptation appears to be based in what’s known as phenotypic plasticity — the ability of a creature to respond to changes in its environment — rather than natural selection favoring birds with earlier breeding times.

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