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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Your Forest or Mine?
1 June 2001 7:00 pm
The males of a bird species thought to live exclusively within forests while breeding actually fly frequently across other kinds of habitat, researchers have found ... and they do so to search for extramarital sex. The finding shows how probing an animal's behavior can help determine its conservation needs.
Ornithologists have long voiced concern over human fragmentation of forests. They've found that birds that dwell inside a forest fragment often suffer from decreased availability of food, more attacks on their nests from predators, and increased egg parasitism. Such factors are thought to determine the minimum size of forest patches birds need.
Like many temperate-breeding migrant birds, hooded warblers in continuous forest cheat on their partners so often that fully one-third of their offspring result from extrapair copulations. You might expect their sex lives to be much duller when warbler pairs are isolated in remote fragments. "Wrong!" says behavioral ecologist Bridget Stutchbury of York University in Toronto; DNA fingerprinting has shown that 20% of the young in fragments are sired by intruding males. So Stutchbury and her student Ryan Norris, now at Queens University in Kingston, Ontario, tracked male warblers using radio transmitters and closely observed their behavior. As it turned out, the males left their home fragments up to several times a day, and what they were looking for were new females.
The good news for avian conservation is that male hooded warblers frequently cross gaps of up to 450 meters, and they don't seem to require corridors connecting forest patches. "These 'shy forest birds' are boldly flying across cornfields," Stutchbury says. However, shuttling among fragments takes energy, which is why larger tracts of forest are a more attractive place to live. Indeed, many small fragments lack any warbler pairs at all, even though in the warbler's case, they are no worse than continuous forest in terms of food, predation, or parasitism.
Other researchers praise the work for tying sexual behavior to habitat use. Biologists have made many assumptions about the effects of fragmentation without looking closely at animals' behavior, says behavioral ecologist Steven Lima of Indiana State University in Terre Haute, "so we can scarcely avoid being surprised when we start following animals around to see where they're going and what they're doing."