News of the Wild
From the June/July 2010 issue of National Wildlife
Roger Di Silvestro
These Birds and Bees Will Remember You
Biologists wearing caveman masks while banding wild crows have found that as much as four years later, the birds loudly scold an individual who approaches them while wearing the mask. The birds ignored the same person wearing a Vice President Dick Cheney mask, which no one had worn while handling the birds. “It’s important for the birds to keep track of danger,” says John Marzluff, a biologist at the University of Washington who led the study, though he was surprised at how long the crows remembered the threatening mask. Similarly, researchers at France’s University of Toulouse have found in tests that honeybees can tell a drawing of one human face from a drawing of another, an ability to recognize patterns that “may allow bees to categorize objects of interest like flowers,” says Martin Giurfa, one of the researchers.
The Katy Did It
Husband-and-wife cicada experts from the University of Connecticut, while studying cicadas in Australia, found a form of predatory behavior that turns mating calls into arias of death. Dave Marshall and Kathy Hill discovered that the spotted katydid, an Australian bush cricket, will respond to the mating calls of male cicadas with a perfect imitation of the female cicada’s come-hither signal, composed of simple clicks “made with precise timing in relation to the male cicada’s song,” Marshall says. When the male cicada zooms in for lovemaking, he finds not the creature he longed for but a much larger, and quite hungry, katydid that ambushes and eats him.
Bright Male Birds Make Better Mates
A new study of the great tit, a European songbird, has found that brightly colored males produce the healthiest sperm, making them the better mates. Why? Because the species’ yellow breast plumage is colored by chemicals called carotenoids, which are important to a bird’s ability to cope with stress. Evolutionary ecologist Fabrice Helfenstein, of Switzerland’s University of Bern, found that within five days after he added two extra chicks to the nests of wild great tits, the increased workload caused a greater reduction in sperm activity in paler males than in brighter males. It seems that the carotenoid-laden, brighter males adapt better to hard times. Feathers are grown only during molt, a stressful time for birds that lose flight feathers. Possibly, Helfenstein says, “an individual good at coping with stress during molt is likely to be good at coping with stress anytime.”