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Wikimedia Commons

Birds Steer Clear of Invisible Roads

Wikimedia Commons
Wikimedia Commons

Forget about whether the chicken crossed the road or not. The question for some scientists is why other birds won’t even come near a roadway. 

Wherever wildlife and automobile traffic meet, it’s usually bad news for the animals. More than just making roadkill, roads use up land, create noise and pollution, and act as barriers that cut animals off from resources, mates, and territory. Because of all these problems, bird populations tend to decline sharply within a kilometer of a road or other human infrastructure, and mammals begin declining within five kilometers. 

You’re within about a kilometer away from a road in more than 80 percent of the USA. That’s a whole lot of country covered in things that bug birds. But what bothers them most? The trash? Close calls with windshields? A lot of research has suggested that it's the level of noise around a busy roadway, but most of these studies have been done along actual roads. When all the potential bird-deterring effects are there at the same time, it’s hard to pin down the strength of any single one. 

To isolate the noise factor and see how much it matters to birds, biologists from Boise State University in Idaho wanted a way to create traffic noise without actual traffic. They decided to hide speakers in the trees of a southern Idaho forest that migrating birds use as a rest stop. When they piped recordings of traffic sounds through the speakers, they had a half-kilometer-long “phantom road” that wouldn’t bother the birds any way but through their ears. 

The Road Not Taken

Alternating between four days of noise and four days of quiet throughout the fall migration season, the researchers recorded visits of more than 8000 individual birds from 59 species to their phantom road and a noise-less control site. Whenever they turned the speakers on, the total bird abundance at the phantom road declined by more than a quarter. Some species avoided the area in even greater proportions, and a few, like the cedar waxwing, avoided it almost entirely.

Scaring away that many birds with only traffic noise is a startling demonstration of how man-made noise can alter the way animals use space. Because of the sheer amount of land that roads cover in the U.S., particularly noise-sensitive species like the waxwings and yellow warblers are pushed away from a whole lot of otherwise useable habitat because it’s too loud for them. 

Even within national parks and other protected areas, the researchers say, roads can produce noise levels similar to their phantom road, and man-made noise needs to be taken into account when preserving and managing land and wildlife. The next step is figuring out why noise is such a big deterrent for birds. It could be that noise masks birds’ songs and calls and keeps them from finding or communicating with one another. Other scientists have found that birds with high-frequency songs aren’t as bothered by roads and certain industrial sites because these low-frequency noises don’t drown out their songs as much as they do some other species. 

Road noise might also turn birds away because it keeps them from hearing predators. Some birds, like chaffinches, and other animals are more vigilant in noisy areas so other animals don’t get the drop on them, often at the expense of eating or other normal behaviors. If more noise means less eating, then roads are especially lousy places to be when a bird is migrating and needs fuel to keep going. 

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Big Questions
Why Do Cats 'Blep'?
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As pet owners are well aware, cats are inscrutable creatures. They hiss at bare walls. They invite petting and then answer with scratching ingratitude. Their eyes are wandering globes of murky motivations.

Sometimes, you may catch your cat staring off into the abyss with his or her tongue lolling out of their mouth. This cartoonish expression, which is atypical of a cat’s normally regal air, has been identified as a “blep” by internet cat photo connoisseurs. An example:

Cunning as they are, cats probably don’t have the self-awareness to realize how charming this is. So why do cats really blep?

In a piece for Inverse, cat consultant Amy Shojai expressed the belief that a blep could be associated with the Flehmen response, which describes the act of a cat “smelling” their environment with their tongue. As a cat pants with his or her mouth open, pheromones are collected and passed along to the vomeronasal organ on the roof of their mouth. This typically happens when cats want to learn more about other cats or intriguing scents, like your dirty socks.

While the Flehmen response might precede a blep, it is not precisely a blep. That involves the cat’s mouth being closed while the tongue hangs out listlessly.

Ingrid Johnson, a certified cat behavior consultant through the International Association of Animal Behavior Consultants and the owner of Fundamentally Feline, tells Mental Floss that cat bleps may have several other plausible explanations. “It’s likely they don’t feel it or even realize they’re doing it,” she says. “One reason for that might be that they’re on medication that causes relaxation. Something for anxiety or stress or a muscle relaxer would do it.”

A photo of a cat sticking its tongue out
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If the cat isn’t sedated and unfurling their tongue because they’re high, then it’s possible that an anatomic cause is behind a blep: Johnson says she’s seen several cats display their tongues after having teeth extracted for health reasons. “Canine teeth help keep the tongue in place, so this would be a more common behavior for cats missing teeth, particularly on the bottom.”

A blep might even be breed-specific. Persians, which have been bred to have flat faces, might dangle their tongues because they lack the real estate to store it. “I see it a lot with Persians because there’s just no room to tuck it back in,” Johnson says. A cat may also simply have a Gene Simmons-sized tongue that gets caught on their incisors during a grooming session, leading to repeated bleps.

Whatever the origin, bleps are generally no cause for concern unless they’re doing it on a regular basis. That could be sign of an oral problem with their gums or teeth, prompting an evaluation by a veterinarian. Otherwise, a blep can either be admired—or retracted with a gentle prod of the tongue (provided your cat puts up with that kind of nonsense). “They might put up with touching their tongue, or they may bite or swipe at you,” Johnson says. “It depends on the temperament of the cat.” Considering the possible wrath involved, it may be best to let them blep in peace.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Animals
Why Crows Hold Noisy Funerals for Their Fallen Friends
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The next time you hear a murder of crows cackling for no apparent reason, show a little respect: You may have stumbled onto a crow funeral. Crows are among the few animals that exhibit a social response to a dead member of their species. Though their caws may sound like heartbroken cries, such funerals aren't so much about mourning their fallen friends as they are about learning from their mistakes.

In the video below from the PBS series Deep Look, Kaeli Swift, a researcher at the University of Washington's Avian Conservation Lab, investigates this unusual phenomenon firsthand. She familiarized herself with a group of crows in a Seattle park by feeding them peanuts in the same spot for a few days. After the crows got used to her visits, she returned to the site holding a dead, taxidermied crow and wearing a mask and wig to hide her identity. The crows immediately started their ritual by gathering in the trees and crying in her direction. According to Swift, this behavior is a way for crows to observe whatever might have killed the dead bird and learn to avoid the same fate. Flocking into a large, noisy group provides them protection from the threat if it's still around.

She tested her theory by returning to the same spot the next week without her mask or the stuffed crow. She offered the crows peanuts just as she had done before, only this time the birds were skittish and hesitant to take them from her. The idea that crows remember and learn from their funerals was further supported when she returned wearing the mask and wig. Though she didn't have the dead bird with her this time, the crows were still able to recognize her and squawked at her presence. Even birds that weren't at the funeral learned from the other birds' reactions and joined in the ruckus.

Swift was lucky this group of crows wasn't particularly vengeful. Crows have been known to nurse and spread grudges, sometimes dive-bombing people that have harmed one of their own.

[h/t Deep Look]

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