Owls Use Dung to "Fish" for Beetles
John Roach for National Geographic News

Burrowing owls have an affinity for the dung of other animals. Their underground nests and surrounding areas are carpeted with the stinky stuff. Now a team of researchers has found at least one reason why all this fecal matter matters to the owls: It's bait for dung beetles, the owls' favorite grub.
The research, reported in the science journal Nature, demonstrates that burrowing owls (Athene cunicularia) deliberately use mammal dung as a tool to reel in a meal—and in the process substantially increase the number of dung beetles they eat.

"Burrowing owls are diurnal [active in daytime], they will sit at the burrow entrance all day long and it looks like they're doing nothing," said Douglas Levey, a zoologist at the University of Florida in Gainesville. "But you know what? It's pretty clear they are fishing. They've got their line in the water and are waiting for dung beetles to come by."
Levey, who is the lead author of the study, added that the finding is particularly noteworthy because it demonstrates that tool use can substantially benefit a wild animal. Such convincing evidence is scant in the biological record.
For example, herons are widely known to place a floating object, such as a bread crumb or feather, on top of water as a lure for minnows. But no studies have compared how well herons would do if they did not fish in this manner.
"As far as I know, [our study] is the first example of that, not just in birds but in wild animals in general," Levey said.
Gavin Hunt, an ecologist at the University of Auckland in New Zealand who studies tool use by crows, agrees.
"The owl paper is the first to really quantify the benefit of tool use to a free-living animal in terms of food gained," he said. "As such, it is an interesting finding that seems to confirm what most of us have only assumed to date."
Experiment
The researchers came up with the study idea several years ago while on a field trip to observe burrowing owls. It was part of an ornithology course Levey was teaching at the University of the Florida.
Levey and his students—including study co-authors Scot Duncan, now at Birmingham-Southern College in Alabama, and Carrie Levins, who lives in Panama City, Florida—noticed dung scattered around the burrow and wondered why it was there.
Duncan, whose wife happens to be a beetle expert, recognized beetle parts in the regurgitated pellets that were mixed in with the dung. He realized that the owls were eating a bunch of beetles.
"Everybody who studies burrowing owls knows they bring dung back to their burrows, and they know that burrowing owls eat a lot of dung beetles. But nobody had put two and two together," Levey said.
To test the hypothesis that the burrowing owls were indeed luring the dung beetles to their nests with dung, the researchers removed dung and pellets from several burrows. They then placed fresh dung at the entrance to some and left others bare.
Four days later the researchers examined the owls' regurgitated pellets and found that the owls with dung bait ate ten times more dung beetles and six times more dung beetle species than the owls without dung bait.
Wise Owls?
But before you go out and buy your favorite burrowing owl a kitschy "gone fishin'" sign to hang on the burrow wall, Levey said there is no evidence to suggest the owls are actually aware of what they are doing.
"Even though people think owls are wise, there's no reason to assume they make a conscious choice to go get the dung they bring back because [they know] beetles will then appear out of nowhere," he said.
Rather, according to Levey, this dung beetle baiting behavior is likely a trait that evolved via natural selection: Owls that bring back more dung are more likely to get more dung beetles and thus are more likely to be successful in reproduction, passing on the trait.
"The owls are using a rather simple method to catch beetles with readily available material, so the raw material—owls, dung, and dung beetles—if you like, was just waiting for evolution to come up with tool use," Hunt, the New Zealand ecologist, said.
In fact, Levey doubts that the behavior of bringing dung back to the burrow evolved for the reason of dung beetle baiting. Owls bring other stuff back to the burrows, including bits of plastic, carpet tailings, foil, and gum wrappers, all of which may serve as insulation. Or, the dung may serve to camouflage from predators the scent of eggs or chicks.
The researchers tested the egg hypothesis using quail eggs and found that nests with and without dung were equally attacked by predators. However, the test did not rule out the possibility that chicks give off a smell that the dung masks.
"We didn't test that. We didn't want to sacrifice chicks, so the olfactory hypothesis may yet hold," Levey said.
Regardless, the researchers' finding that the dung beetle baiting behavior benefits the owls' diet is generally held to be valid.
"I'm convinced that owls with dung outside their burrows catch more dung beetles than when the dung is not there," Hunt said. "That doesn't rule out another advantage of having the dung around the burrows, though."
Levey said, "It's often the case that one behavior can do more than one thing, and there's nothing wrong with that."

(When told about this behavior, my daughter Samantha asked the big question, "But how do they carry it home?" D.B.)

Just how smart animals are, how capable of interspecies communication, and what's wired in and what's not, are constant topics amongst the open minded observers in Central Park.
Below find lessons in never underestimating of what they may be capable.

Prairie Dog Communication
and Dr. Con Slobodchikoff

“Basically, prairie dogs are a universal lunch item. Everybody likes to feed on prairie dogs,” says animal behaviorist Con Slobodchikoff of Northern Arizona University. And the prairie dogs know that. When a predator approaches they emit a series of warning chirps.

Talking Prairie Dogs
Prairie dogs can talk. At least that’s the startling conclusion reached by Slobodchikoff.
His research flies in the face of conventional scientific thinking on the subject of animal intelligence.
He maintains that prairie dogs can convey complex information through a language more sophisticated than that of any animal ever studied.
Slobodchikoff has documented more than 100 prairie dog words all revolving around the same subject: predators. From his observation tower on the edge of a prairie dog colony outside Flagstaff, Slobodchikoff operates a directional microphone, a tape recorder and a video camera. From this vantage point, he can spot intruders, such as hawks, cats, dogs, and men and record the alarm calls these potential threats trigger in the prairie dogs.

“Each time we do experiments I’m surprised because each time even I don’t think these animals have the capabilities that our experiments show them to have,” says Slobodchikoff.

Back at his lab he digitizes his audio field tape into sonograms which show what each alarm call “looks” like, complete with adjectives.
The professor has discovered that prairie dogs use adjectives to differentiate objects. For example, they can describe the color of clothes on a human and whether he is tall or short. They can also describe how fast a man is moving or whether he is carrying a gun. And there’s evidence that the animals can remember that specific person for up to two months.

Each prairie dog colony appears to have its own dialect, much like New Yorkers sound different from Southerners. But researchers believe the basic language is the same. That is, a prairie dog from Arizona could talk to a prairie dog from New Mexico.

Animals vs. Humans
Despite the documentation, the notion that the lowly prairie dog could have such a complex communication system is still met with some skepticism. Slobodchikoff explains that some people don’t believe animals are capable of cognitive functions.

Renowned biologist Jane Goodall knows something about that prejudice.“Every time some new discovery appears, there is an instant hostile reaction, not necessarily from the scientists but also from religious people in some cases,” says Goodall.

“There is a real strong need in the minds of many people to keep that line sharp between humans on the one hand and the rest of the animal kingdom on the other. I think the chimp, more than anything else, has helped to blur that line.”

Goodall’s work with the chimpanzee documented cognitive and emotional capabilities in that primate. But the idea that chimps could actually think and feel met with initial resistance. For example, when she used human pronouns to describe chimpanzee behavior.

“The first paper I wrote for “Nature,” the scientific periodical, they actually crossed out where I put “he and she and who,” and put “it” which, I thought, this is crazy. So we have come a long way since then.

Prejudice About Rodents But the prairie dog still has an image problem. This is no primate, with humanlike expressions. This is a lowly rodent.

“The prejudice is that lowly rodents have to be by definition fairly stupid. Therefore what I’m finding must be a mistake in the minds of at least some people,” says Slobodchikoff.

Not everyone who deals with prairie dogs is interested in their language skills. Ranchers say they are pests that ruin grazing land and carry bubonic plague. Slobodchikoff says the prairie dog’s reputation as a pest is exaggerated, and its potential contribution to research underestimated.

The Lessons of Prairie Dogs
After all, says the professor, if prairie dogs have the ability to think and communicate, perhaps other species can do the same.

“If animals can think, if they have self-awareness, this sort of raises an ethical question about what it is we are doing with animals and how we really should treat animals,” he says.
Goodall agrees but is not optimistic.
“It doesn’t happen that way. The resistance continues. We go on trying to convince ourselves that we are different. That we are special,” she says. Of course, there are differences. After all, the prairie dog is not spouting poetry. But when it comes to the basic prose of survival, he’s got it down.

http://abcnews.go.com/onair/CloserLook/wnt_000303_CL_AnimalLanguage_feature.html



Cognition and Communication in Prairie Dogs
by C. N. Slobodchikoff

My central research question concerns the relationship between the complex communicationsystem of Gunnison's prairie dogs and their cognitive abilities. Gunnison's prairie dogs (Cynomys gunnisoni) are social, colonial animals that are found in the American Southwest,within the states of Arizona, New Mexico, Utah, and Colorado.

There are four other species of prairie dogs: the Black-tailed prairie dog (Cynomys ludovicianus), found in the midwesternUnited States; the Utah prairie dog (Cynomys parvidens), found in the state of Utah; the White-tailed prairie dog (Cynomys leucurus), found in the states of Montana and Wyoming; andthe Mexican prairie dog (Cynomys mexicanus), found in the state of Chihuahua in Mexico.Gunnison's prairie dogs typically spend the winter in a state of torpor inside extensiveunderground burrow systems, then emerge in the spring to set up territories (Slobodchikoff1984; Rayor 1988). Each territory is defended by the group living on it, and the social structure can vary considerably within the same colony. Some territories are occupied by a single male or female, others are occupied by a single male and a single female, still others are occupied by a single male and several females, and some are occupied by several adult males and several adult females (Slobodchikoff 1984; Travis and Slobodchikoff 1993). The structure of the social system within a territory seems to be correlated with the distribution of food resources: uniformlydistributed food resources correlate with single male-single female territories, while patchily distributed food resources correlate with single male-multiple female and multiple male-multiple female territories (Slobodchikoff 1984; Travis and Slobodchikoff 1993).

The colonies are spatially fixed, and the extensive burrow systems can persist for perhaps hundreds of years.The spatial concentration of prairie dogs into colonies means that a number of predators can encounter a dependable food source throughout much of the year. Prairie dogs are preyed upon by coyotes, foxes, badgers, golden eagles, red-tailed hawks, ferruginous hawks, harriers,black-footed ferrets, domestic dogs, domestic cats, rattlesnakes, and gopher snakes. Also, prairie dogs are hunted extensively by humans for target practice and sport.

Prior to the introduction of rifles, prairie dogs were hunted as a source of meat by Native American peoplesfor at least 800 years (Slobodchikoff et al. 1991). Such predation pressure was probably important for the evolution of anti-predator defenses.

Prairie dogs have dichromatic color vision (Jacobs and Pulliam 1973) and can detect the presence of a predator from long distances. They also have an alarm call system that allows them to advertise the approach of a potential predator. The alarm calls are very loud and can carry for distances of more than a kilometer (Hoogland 1996). The burrows provide an escape route from most terrestrial and aerial predators.

The burrow architecture within a territory has several openings to the surface connected to a series of underground tunnels that can run a horizontal distance of more than 10 meters below the ground surface (Fitzgerald andLechleitner 1973). The alarm call system has proven to be a Rosetta stone for deciphering the information encoded in the prairie dog vocalizations.

When a prairie dog detects a predator, he or she emits a call that alerts other prairie dogs to the presence of danger. The call can be given as a single bark, or as a series of barks that comprise a calling bout. The external referent, the predator, can be seen and videotaped by field observers, as can the escape behaviors of the prairie dogs in response to the predator.

The alarm calls can be recorded on audiotape and brought back to the laboratory for analysis. The calls can be analyzed through Fast-Fourier transform to assess the acoustic structure of the vocalizations. Different parts of the waveforms of the calls can be measured, and statistical analyses or fuzzy-logic neural net analyses can be performed to determine whether calls elicited by different predators are similar to one another or different from each other (Slobodchikoff et al. 1991; Placer and Slobodchikoff 2000). The calls recorded for each predator can be played back to the prairie dogs when no predator is present and when no prairie dog is calling.

Key Terms & Common Behaviors
Chirking: At the first sign of trouble this alarm call is sounded. This is a "chirk-chirk-chirk" sound.

Coterie: A family group of prairie dogs made up of 1 male, 1 to 4 females and their young, up to two years old.

Jump-yip: A strong arch of the back (the "jump"), followed by a shrill "yip". This occurs when a predator has left the area and in territorial displays.


Kissing: Family members greet with what looks like a kiss. They're not really kissing, but gently touching their front teeth together. This is how prairie dogs recognize each other.





Next Time You See A Prairie Dog, Ask About The Wife And Kids
By Leo Banks

CON SLOBODCHIKOFF is a soft-spoken, Berkeley-educated scientist with a shock of silver hair and a stout backbone. He needs the latter to endure the raised eyebrows of colleagues who can't bring themselves to accept the conclusion Slobodchikoff has reached through 10 years of painstaking research--prairie dogs can talk.

Yes, talk. As in tell family and friends of approaching predators, identify the predator, and in the case of humans, describe the clothing and even whether he or she is carrying a gun.

In the world of this animal behaviorist, born to Russian parents, now a professor at Northern Arizona University, prairie dogs are nothing like the rapidly procreating rangeland critters of popular image. He describes them as highly intelligent and capable of conveying complex information through a vocal language more sophisticated than that of any animal ever studied.

For years scientists thought animals could only give calls about their emotions, such as anger or fear. But Slobodchikoff says the more he analyzed the communication of prairie dogs, the more complicated the story got. "The Rosetta Stone of this is the prairie dog's alarm call," he says.

Slobodchikoff gathers data by sitting inside a tower on the edge of a prairie dog colony in the pine forests outside Flagstaff. The wood-frame structure is covered in burlap for concealment. Inside, he operates a directional microphone, tape recorder and video camera.

When a predator approaches, prairie dogs make a sound like a bird chirping, and Slobodchikoff records it. Back in the lab, he runs the tape through a computer program that digitizes it, and breaks it down into frequency and time. Changes in frequency and time are measured, and this data re-entered into the computer and analyzed to see if differences exist between predators.

They do. The alarm call for an approaching hawk, for instance, is different from that of a coyote, which is different from that of human.

In one experiment, Slobodchikoff had a gun-toting hunter appear in a prairie dog colony. The call the dogs gave for that person was distinct from the call they gave for another who appeared without a gun. For the next two months, the first hunter returned periodically, but without a gun. The prairie dogs remembered him as a potential threat and always gave the same call as when he had gun.

The only animal with comparable language ability is the vervet monkey of Kenya. It has calls for three predators, eagle, leopard and snake. Slobodchikoff's research has identified prairie dog calls for four predators--human, hawk, coyote and domestic dog. Badgers also prey on prairie dogs, but he has been unable to distinguish an alarm call for badgers.

Counting its predator words, and numerous adjectives to modify them by color, shape, size and more, Slobodchikoff places the numbers of words prairie dogs can speak in the hundreds.
They also have a kind of grammar--they can speed up or slow down their talking depending on whether the predator is running or walking through their colony. Slobodchikoff calls it a grammar because it follows the basic rules of how you combine sounds, the same way humans do.

And prairie dogs have varying dialects. Every colony pronounces words in a slightly different way, but dogs within the same species can communicate. In other words, a Gunnison Prairie Dog from Colorado could chat with a Gunnison Prairie Dog from Utah.

"My interest is in finding out if other animals can do this, too," he says. "Scientists haven't really thought to look because they just expected that animals couldn't talk."

But it's tough to get funding. A two-pound varmint talking to other two-pound varmints? It sounds too far out. Except to ordinary folks. Non-scientists are fascinated to learn that animals can talk, and don't think it's strange at all. In fact, they're surprised that more researchers aren't studying the question. Scientists are a much harder sell.

"I'd say 25 percent think my findings are interesting," says Slobodchikoff. "And 75 percent are either agnostic or outright disbelievers. When I first presented my research, colleagues told me I must've made a mistake."

ANOTHER OBSTACLE is overcoming anti-prairie dog sentiment. Hunters delight in finding them at the end of their gunsights, various government agencies are more than happy to tell you how to poison them, and ranchers complain that they carry bubonic plague. They also leave holes in the ground that can trip up horses, and they're worse than cows at stripping landscape of vegetation.

"They're a pain in the neck," says C.B. "Doc" Lane, spokesman for the Arizona Cattleman's Association. "They can do enormous damage to a field. They build entire prairie dog towns that can be 10 acres in size."

"If you drive from Denver to Boulder, in the Douglas County area, you'll see large plots of land with no forage at all," says Reeves Brown, executive vice president of the Colorado Cattlemen's Association. "They've been stripped clean and people think it's from horses and cows. But it's prairie dogs."

Brown recommends a little poison barley at the edge of the colony and a change in attitude: 'If we called them prairie rats, it'd be hard to have much sympathy for them."

Barley is only one way to skin a pest. The University of Arizona's agricultural agent in Coconino County, Slobodchikoff's home, hands out literature to anyone interested in getting rid of prairie dogs. Tips include using strychnine, toxic gas, trapping, shotgunning and pumping carbon monoxide into their burrows.

The latter is accomplished by dropping a cartridge inside, or running exhaust from a car or truck into the hole. "Actually a lawn mower would do the trick," says agent Tom DeGomez, who says two cases of plague in humans in Coconino County have been linked to prairie dogs.

He tells people the long-term solution is to plant trees. "They don't like trees because they like to pop their heads up and look around to see who's coming. They're paranoid," says DeGomez.

Paranoid? Hard to understand why. Navajos and Hopis have only been hunting them with spears and arrows for hundreds of years, and they even have traditional recipes for baked prairie dog. It's considered a delicacy.

"They're everybody's lunch," says Slobodchikoff. "Here's an animal people think of as simplistic vermin, yet it has a complex cognitive brain that can form concepts and remember things for long periods. I think prairie dogs have a lot to teach us."

http://www.tucsonweekly.com/tw/07-17-97/curr1.htm

Black-crowned Night-heron Nycticorax nycticorax

A bit before dusk, nearly every evening these days, a Black-crowned Night-heron mysteriously appears, not a muscle moving, peering through the reeds, on the little island just south of Gapstow bridge. Capable of complete stillness for extended periods of time, screened by vegetation, and blending into the rise of rock behind him, you may not notice him at first. Which is exactly the point after all for a bird on the hunt.

Unless of course he's undertaking the process of daily grooming, a tremendously vigorous act for a creature of usual stealth. In fact there is so much movement even preteens on bicycles may take notice. They'll be walking their bikes across the bridge, the decibel level high as they top one another in telling their adventures of the day, when suddenly one will stand rooted, and say, "Look at that! Is it a penguin?."

The heron may continue his absolutions, while keeping an eye on the noise makers until they drift out of sight. When he's finished his feathers, it is back again to that marvel of stillness and hope for a possible snack, before flying into a tree around civil twilight time. It is not always the same tree, but it will be near the pond.

On Saturday, one of the Black-crowned Night-herons chose a tree placed just north of the bridge. Within a short time, a second Night-heron made either for the same spot or for the heron sitting in it, and at the last moment before collision took an abrupt right turn in the air before sweeping grandly off into the night. Though a very close encounter, the first heron , as one might suspect-- did not move a muscle.