Ok, not necessarily a VA/DC Bird thing, but still interesting. =
Burrowing Owls using tools and Ravens eating Eared Grebes in =
Yellowstone.
Denise Ryan
Washington, DC
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Scientific American.com
September 02, 2004 =20
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Cunning Owls Bait Beetle Prey =20
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The wise old owl is a staple of nursery rhymes. New findings provide =
more evidence that the animals are, in fact, quite crafty. According to =
a report published today in the journal Nature, owls use mammal dung to =
lure prey.=20
A few examples of avian tool use have been reported, but in many cases =
the birds were captive animals and it was difficult to assess the =
advantage their wild counterparts could glean from the behavior. In the =
new work, Douglas J. Levey of the University of Florida and his =
colleagues studied wild populations of burrowing owls (Athene =
cunicularia). The researchers removed all traces of mammal dung from the =
nests of two owl populations in Gilchrist County, Fla. Half of the nests =
then received an amount of dry dung typically found surrounding a nest. =
After four days, the researchers analyzed the birds' droppings and =
collected discarded remains of eaten beetles to determine the owls' =
diets. They discovered that owls with access to dung ate 10 times more =
dung beetles than those with bare nests did.=20
The scientists also tested whether the owls might be using the dung to =
mask the scent of their nests, but found that it did not offer =
sufficient protection from predators. Instead, the owls appear to "fish" =
for dung beetles using excrement as bait. The results of this study, the =
authors conclude, provide "an unambiguous estimate of the importance of =
tool use in a wild animal." --Sarah Graham=20
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Subject: Scientist writes about bird massacre ( Article in 8/30 Billings
Gazette and Bozeman Chronicle)
Scientist writes about bird massacre Associated Press
BOZEMAN (AP) - A Yellowstone National Park ornithologist who saw four
ravens systematically kill 141 grebes describes the spectacle in the =
new issue of Yellowstone Science, a quarterly magazine.
Terry McEneaney had known for a long time that ravens are efficient =
predators. But he was astonished last May when he saw four of them =
attack so many grebes on icy Yellowstone Lake. Western-eared grebes =
generally do not spend much time in Yellowstone, but on May 1 hundreds =
passed overhead, en route north for the summer. McEneaney was at the =
lake, looking for bald eagle nesting sites, when he saw a grebe on the =
frozen water. Shifting cloud shadows apparently had fooled the bird into =
thinking it was landing on open water. "Then I saw another grebe, and =
another grebe, and another grebe,"McEneaney said. "They were all over =
the place." Grebes need open water for takeoff, so once they landed, =
they were stuck there. Enter the ravens. At first, only one was on the =
ice. It "flew out to one of the stranded grebes and pulverized it with =
its long beak until it was dead," McEneaney wrote in the magazine. The =
raven left the grebe where it lay, then moved to another and pecked it =
to death, as well. At about 11 ounces, grebes are much smaller than =
ravens. Twenty minutes later, three more ravens joined in and started =
killing grebes. Then two bald eagles showed up and began eating the =
grebes the ravens had killed. McEneaney watched for three hours and =
kept track of the action. After the ravens had killed 92 birds, they =
began dismantling the carcasses and flying to the shore, where they =
cached the grebe meat in the snow, said McEneaney, who has studied =
ravens for nearly 20 years. "When there's an abundance of food, they =
cache it," he said. "They went back and forth, back and forth."He had to =
leave, but when he returned at day's end, all 141 grebes were dead. =
McEneaney said he has watched ravens carry off 13 baby magpies, pluck =
trout from a stream and even try to peck a mired bison to death, =
starting with its eyes. What he saw at Yellowstone Lake in May topped it =
all. "I've never seen anything of this magnitude," he said. "I didn't =
believe they could do that much predation in one day." McEneaney said =
he never considered trying to intervene. The ice was not safe, and park =
regulations require Mother Nature be allowed to take its course. "That's =
what it's all about," McEneaney said. "As gruesome as it sounds, it was =
really interesting to watch. It's etched in my mind."
Copyright =A9 2004 Associated Press
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