It brings other birds out of the trees to "mob" the predator and chase it away. Birds make that call when they see a perched predator. Greene demonstrates by pressing his lips to the back of his hand and making an irritating sound like screeching tires. "It's very high frequency," he explains, "and it's hard to locate." Like any self-respecting birder, Greene can imitate this alarm call exactly. It warns other birds by making a soft, high-pitched seet call. A small bird spots a dangerous predator - let's say a hawk or owl - flying around. Recently, a biologist using a similar technique discovered something no one had imagined - that these bird warnings are adopted, and passed along, by completely different types of animals.Īt his lab at the University of Montana, biologist Erick Greene explains how this works. He was just 40 years old.Įven after Parker's death, his technique of provoking birds to reveal their behavior stuck with other scientists. Parker was doing just such a bird census in Ecuador when he died in a plane crash in 1993. The only good census that's been done in a rain forest was done that way - by mapping counter-singing pairs." You can map all the territories in a forest eventually. Then I move farther on until I get the next pair. I can quickly draw those territories on a map. "I get a pair here, a pair there - a pair behind me there. "What I try to do is arouse them all," he said. "If you are outside their territory and you play back a song," Parker said in 1991, "the birds will come up only to the edge of their territory." Perched on the boundary, he noticed, the pair would start to vocalize - in essence, shouting, "Hey, get out of here!" That confused the pair - they seemed to think that outsiders were threatening to invade. So, how did he provoke them? Parker recorded the calls of a mating pair, then played their own song back to them. Ted Parker, a pioneering ornithologist who died in 1993, has been called the "Mozart of ornithology." He memorized the sounds of more than 4,000 species, and used recordings of calls to get birds to reveal their territories. If he could provoke the pairs - challenge the birds somehow to defend their little patch of forest - they would reveal their location and the extent of their territory. Here's how: Parker realized that each mating pair of birds has its own territory. Who lived in which part of the canopy? And how do you find that out, if you can't see them? He wanted to know how birds divide up their territory. "And if you don't know their voices, there's no way you could come to a place like this and come up with a good list of canopy species." "These birds spend all their time in that foliage that's 130 to 140 feet above the ground," Parker explains on the tape. He used this knowledge and his tape recorder to quickly take an extensive and detailed census of birds in the tropics. He'd memorized the sounds of more than 4,000 bird species. Some called Parker the Mozart of ornithology. "I spent hours moving the needle back and forth, and back and forth, and my mother would say, 'You are going to destroy the record player.' " "My parents bought me records of bird recordings that were made by people at Cornell," Parker told the NPR team in 1991. His skill in using his ears to investigate the world was legendary. Parker was an ornithologist with Conservation International who spent months at a time in the tropics, lugging around a portable tape recorder. "Up here in the canopy, these are the hardest birds to detect," he told an NPR Radio Expeditions team in 1991 in the Bolivian rain forest. Let's fast forward 45 years and talk to Ted Parker, who inherited Allen's gift for recording birds, but added a twist. Ornithologist Arthur Allen of the Cornell Lab of Ornithology was a pioneer, hauling bulky recording gear into the wilderness in the 1940s and actually cutting acetate records of bird song on-site. In a series called Close Listening: Decoding Nature Through Sound, Morning Edition has been profiling scientists who explore the natural world by listening to it.īut sometimes listening isn't enough - scientists have to record animals and even talk back to them to figure out what they're saying. Squirrels closely mimic bird warning calls and help spread the alarm through the forest that hawks, owls or other predators are nearby.
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