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Can Birds Smell?

Legendary birdman John James Audubon would tell you decisively that, no, birds can't smell. In the 1820s, Audubon designed two experiments to prove that turkey vultures followed their eyes, not their noses, to carrion. First, the naturalist left a stuffed deer in a meadow with its legs in the air. Before long, the deer attracted the attention of a vulture, who dropped out of the sky to investigate. Finding nothing but grass inside the fake deer, the vulture took off.

The second experiment took place in the sweltering heat of July. Audubon dragged a decaying pig carcass into a ravine and covered the body with brush. The vultures spotted it, but they weren’t interested. That was that, said Audubon. No smell.

For more than a century, scientists took him at his word. Then, in the 1960s, an ornithologist at the Los Angeles County Natural History Museum named Kenneth Stager realized why vultures ignored Audubon’s carcass in the woods: it was just too gross. Like any discriminating diner, a turkey vulture prefers a fresh carcass [PDF], no more than four days old.

Through rather odd means, Stager learned that vultures actually do use smell. A gas company worker mentioned to him that turkey vultures would congregate around leaks in the pipeline, showing up so reliably that they began to use the birds as leak detectors.

This behavior occurred because the company had added a smelly chemical called ethyl mercaptan to the gas. You know what else gives off ethyl mercaptan? Carrion. Stager was able to tie the two together to suggest that vultures do in fact sniff their way to supper.

Stager wasn’t the only scientist interested in bird olfaction. In 1965, physiologist Bernice Wenzel of UCLA hooked pigeons up to heart monitors and exposed them to strong smells. The pigeons’ heart rates spiked each time a scent wafted their way. Then she attached electrodes to the pigeons’ olfactory bulbs (the smell centers of the brain) and started again. The results were just as dramatic.

In the half-century since, scientists have tested more than a hundred bird species, and all of them have had at least some sense of smell.

At times, their experiments have swerved into the realm of the bizarre. Sensory ecologist Gabrielle Nevitt once soaked super-absorbent tampons in fish-scented oil and tied the tampons to kites, launching them over the sea. The experiment worked a little too well: after a short while, the swarming seabirds were so intense that Nevitt had to bring the kites down in order to keep them from getting tangled in the strings.

Just how much a bird can smell depends on its species. The humble kiwi has one of the strongest senses of smell in the bird family, and it’s the only bird with nostrils at the end of its beak. At night, the kiwis sweep their beak tips along the ground like metal detectors, sniffing out earthworms and grubs.

Eurasian rollers, on the other hand, use scent in self-defense. When threatened, roller chicks vomit up an awful-smelling orange liquid. The stink not only deters potential predators, but it also acts as a warning. When the adult birds return to the nest, the scent tells them that a predator has been, and may still be, near.

Other birds use scent as an instrument of seduction. Crested auklets produce a tangerine-scented oil, which they dab all over their feathers like perfume. The better a bird smells, the better its chances of mating.

The same goes for the pudgy, flightless parrot known as the kakapo, which is said to emit a smell like lavender and honey. The kakapo is extremely endangered—there are only 124 left in the wild—so mating is of dire importance. One researcher even considered creating a synthetic kakapo perfume and applying it to unattractive males in the hopes of boosting their chances.

As for Toucan Sam, the jury's still out.

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Animals
Can You Identify the Different Bird Calls in This Video?
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Listen closely to birds, and you'll notice that their lilting melodies don't always resemble chirps. Beginner birders who want to learn to identify—and mimic—avian songs can get a crash course by watching the video below, spotted by Slate and filmed by Cornell University's Lab of Ornithology.

Produced as part of the Lab of Ornithology's new online course for birding enthusiasts, the video shows students demonstrating 10 different kinds of song. See how many you can identify for yourself—and if you get stumped, visit the Lab's original YouTube post for a full rundown identifying the species behind each song.

[h/t Slate]

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Animals
7 Fun Facts for World Elephant Day
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Happy World Elephant Day! Celebrate the occasion with some facts about everyone's favorite gentle giant. 

1. ELEPHANTS CAN RECOGNIZE OTHER ELEPHANT CARCASSES.

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The University of Sussex's Karen McComb told National Geographic that elephants "become excited and agitated if they come across a dead elephant," and, in particular, will investigate skulls and tusks. McComb teamed up with researchers at the Amboseli Elephant Research Project in Kenya to study the behavior, showing wild elephants a range of objects that included skulls. They found that the elephants examined skulls—and tusks in particular—of their own kind twice as long as other skulls, and examined tusks six times as long as they did pieces of wood. They were even able to recognize elephant skulls with the tusks removed, but didn't show preference for certain elephant skulls over others, which suggests they didn't know which skulls belonged to their own relatives. "Animals that are intensely social in life may be most likely to display an interest in their dead," McComb told National Geographic. "But what goes on in their minds while they are doing this is a total mystery."

2. THEY'RE SCARED OF BEES.

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Forget about mice scaring off elephants: When farmers need to keep elephants away from their crops, they should use bees. Researchers in Kenya discovered that even the recorded sound of buzzing bees was enough to make elephants retreat—and cause them to emit low-frequency sound, inaudible to humans, that warns other elephants. "It's impossible to cover Africa in electric fences," Lucy King, author of the paper, told the Huffington Post. "The infrastructure doesn't exist in many places and it would restrict animals' movement." But something like a bee fence—hives strung on strong wires a certain distance apart that would move when elephants walked into them, disturbing the hives—"could be a better way to direct elephants away from farmers' crops," she said.

3. THEY MIGHT UNDERSTAND POINTING.

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Human adults and babies often use pointing as a way to nonverbally get a message across, but not many other animals grasp the concept. But according to a two-month study of 11 tame African elephants, these pachyderms might be able to: When presented with two identical buckets and pointed in the direction of the one containing food, elephants picked up on the cue fairly consistently: Elephants had a success rate of 67.5 percent (1-year-old humans have a success rate of 72.7 percent). But an earlier study of Asian elephants indicated that they don’t notice pointing gestures, which is a bit of a mystery.

4. ONE ELEPHANT CAN "TALK." 

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Koshik, an elephant in a South Korean zoo, developed the ability to imitate the sounds of five words he's heard from his trainer—annyeong (hello), anja (sit down), aniya (no), nuwo (lie down), and joa (good)—by sticking his trunk in his mouth. The scientists who first noticed Koshik’s ability speculate that he learned to “talk” because he was lonely.

5. THEY'RE DIGITIGRADES.

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It's Latin for "finger walking," and what it means is that elephants walk on their toes (there are five of them, as well a sixth false toe). According to the book Mammal Anatomy: An Illustrated Guidemost of the animals' weight "rests on a broad pad of elastic tissue behind the toes" which "acts as a shock absorber and prevents the skeleton from jolting too much when the animals walk. It also allows elephants to move surprisingly quietly despite their size."

6. AN ELEPHANT PREGNANCY LASTS ABOUT TWO YEARS.

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If you thought being pregnant for nine months was bad, be glad you're not an elephant, which can be pregnant for up to 680 days, according to the BBC. All that time in the oven has a benefit, though: Elephant calves are born with highly-developed brains, capable of learning their herds’ complex social structures and ready to put their trunks to use.

7. NINETY-SIX ELEPHANTS ARE KILLED IN AFRICA EVERY DAY.

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Unfortunately, elephant poaching remains a very big problem: An estimated 35,000 elephants are killed annually, their tusks sold illegally in the ivory market. Do the math, and that comes out to nearly 96 elephants every day. Find out what you can do to help elephants and stop poaching at 96Elephants.org.

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