Tuesday, September 18, 2012

Corvid Brains - Crows and Jays Show Human Traits

There were two very cool stories about corvids in the press last week, one from the University of Washington in Seattle on how crows can remember faces (confirming previous studies) and another from the University of California Davis on the fact that scrub jays mourn their dead, not just individually but as a group.

The cool thing about the crow study was that the researchers developed a less invasive and traumatizing method for conducting the research. Anything that can be done to reduce the trauma is good in my book.

Both of these studies reaffirm the intelligence of corvids in particular and birds/animals in general.

Crows recall faces with human-like brain activity

U. WASHINGTON (US) — Like humans, crows recognize faces and form associations with them—and to accomplish this, the two species’ brains appear to work in similar ways.

Posted by Sandra Hines-UW on Wednesday, September 12, 2012

The findings reveal that similar processes take place in the brains of crows and humans, both of which recognize faces and form positive and associations with them based on experience. "Our approach has wide applicability and potential to improve our understanding of the neural basis for animal behavior," write the University of Washington researchers.

“The regions of the crow brain that work together are not unlike those that work together in mammals, including humans,” says John Marzluff, University of Washington professor of environmental and forest sciences. “These regions were suspected to work in birds but not documented until now.

“For example it appears that birds have a region of their brain that is analogous to the amygdala of mammals,” he says. “The amygdala is the region of the vertebrate brain where negative associations are stored as memories. Previous work primarily concerned its function in mammals while our work shows that a similar system is at work in birds.

“Our approach could be used in other animals—such as lizards and frogs—to see if the process is similar in those vertebrates as well.”

The “caring” and “threatening” masks both have neutral expressions, so the researchers could be sure the crows were remembering and responding to positive or negative associations. 

Marzluff is the lead author of a paper published this week in the online edition of the Proceedings of the National Academy of Sciences.

Previous research on the neural circuitry of animal behavior has been conducted using well-studied, often domesticated, species like rats, chickens, zebra finches, pigeons, and rhesus macaques—but not wild animals like the 12 adult male crows in this study.

The crows were captured by investigators all wearing masks that the researchers referred to as “the threatening face.” The crows were never treated in a threatening way, but the fact they’d been captured created a negative association with the mask they saw.

Then, for the four weeks they were in captivity, they were fed by people wearing a mask different from the first—this one called “the caring face.” The masks were based on actual people’s faces and both bore neutral expressions so the associations made by the crows was based on their treatment.

Awake and active
In most previous neurological studies of animals, the work usually starts by sedating the animals, Marzluff says. Instead, the new approach involved injecting a glucose fluid commonly used in brain imaging into the bodies of fully alert crows that then went back to moving freely about their cages.
The fluid flooded to the parts of the crow brains that were most active as they were exposed for about 15 minutes to someone wearing either the threatening or caring mask.

Then the birds were sedated and scans made of their brains. All the birds were returned to the wild once all the work was completed.

“Our approach has wide applicability and potential to improve our understanding of the neural basis for animal behavior,” write Marzluff and co-authors Donna Cross, Robert Miyaoka, and Satoshi Minoshima, all faculty members with the radiology department. The department funded the preliminary work while the main project was conducted using money from the University’s Royalty Research Fund.

Most neurological studies to date in birds have concerned their songs—how their brain registers what they hear, how they learn and come up with songs of their own. This new approach enables researchers to study the visual system of birds and how the brain integrates visual sensation into behavioral action, Marzluff says.

Stress reduction
Among other things the findings have implications for lowering the stress of captive animals, he says.

“By feeding and caring for birds in captivity their brain activity suggests that the birds view their keepers as valued social partners, rather than animals that must be feared. So, to keep captive animals happy we need to treat them well and do so consistently,” he says.

Intriguingly, Marzluff says the findings might also offer a way to reduce conflict between birds and endangered species on which they might be feeding. In the Mojave Desert, for instance, ravens prey on endangered desert tortoises. And on the West and East coasts, crows and ravens prey on threatened snowy plovers.

“Our studies suggest that we can train these birds to do the right thing,” Marzluff says. “By pairing a negative experience with eating a tortoise or a plover, the brain of the birds quickly learns the association. To reduce predation in a specific area we could train birds to avoid that area or that particular prey by catching them as they attempt to prey on the rare species.”

Collaborative work among neuroscientists and ecologists could be used to better understand the neural basis of cognition in widely diverse animals, says co-author Cross. For example, her suggestion to use the glucose technique prior to brain scans, so the crows could be fully awake, could be used for other animals.
A researchers wore the “caring mask” to feed the crows. (Credit: Jack DeLap/U of Washington)

Source: University of Washington
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Scrub jays react to their dead

Posted On: September 11, 2012

Western scrub jays summon others to screech over the body of a dead jay, according to new research from the University of California, Davis. The birds' cacophonous "funerals" can last for up to half an hour.

Anecdotal reports have suggested that other animals, including elephants, chimpanzees and birds in the crow family, react to dead of their species, said Teresa Iglesias, the UC Davis graduate student who carried out the work. But few experimental studies have explored this behavior.

The new research by Iglesias and her colleagues appears in the Aug. 27 issue of the journal Animal Behaviour.

Western scrub jays live in breeding pairs and are not particularly social birds.

"They're really territorial and not at all friendly with other scrub-jays," Iglesias said.

Working in the backyards of homes in Davis, Calif., Iglesias set up feeding tables to encourage visits from the jays. Then she videotaped their behavior when she placed a dead jay on the ground. She compared these reactions with the birds' behavior when confronted with a dead jay that had been stuffed and mounted on a perch, a stuffed horned owl, and wood painted to represent jay feathers.

On encountering a dead jay, prostrate on the ground, jays flew into a tree and began a series of loud, screeching calls that attracted other jays. The summoned birds perched on trees and fences around the body and joined in the calling. These cacophonous gatherings could last from a few seconds to as long as 30 minutes.

Western scrub-jay at a backyard bird feeder in Davis, CA. UC Davis researchers found the birds gather for noisy "funerals" when they encounter a dead jay. (Photo Credit: Stephanie Macey-Gallow, UC Davis.)
Jays formed similar cacophonous gatherings in response to a mounted owl, but ignored painted wood. When confronted with a mounted jay, the birds swooped in on it as if it were an intruder.

Jays typically gathered within seconds of the first bird calling, Iglesias said. If they did not, the first jay would often fly higher into a tree, apparently to call more widely.

"It looked like they were actively trying to attract attention," she said.

The purpose of the calls seems to be to alert other birds of danger, Iglesias said. But why the calls summon others, rather than warning them off, is unclear. Having more jays present might mean more eyes to locate a predator, or more numbers to drive it away, she speculates.

There might also be a learning component to the gatherings, if they help teach young jays about dangers in the environment, Iglesias said.

While reactions of animals to their dead are sometimes called "funerals," that does not imply that there is an emotional or ritual element to the behavior, Iglesias said. We simply don't know enough about the emotional life of animals to understand that.

But Iglesias isn't ruling it out. "I think there's a huge possibility that there is much more to learn about the social and emotional lives of birds," she said.

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