When a crow dies, the other crows investigate the cause of death

in #animals8 years ago


Many who have heard the melancholy cry of the mourning dove might wonder: Do birds grieve for their loved ones?
For this Saturday’s Weird Animal Question of the Week  Emilie Bouef commented via Facebook: "I heard that ravens do some kind  of funeral when one of them dies. I’d love to know more about this."
Calling to each other, gathering around, and paying special attention to a fallen comrade is common among the highly intelligent corvids, a group of birds that includes crows, jays, magpies, and ravens, says Kaeli Swift, a Ph.D student in environmental science at the University of Washington. (See "Are Crows Smarter Than Children?")
But it doesn't necessarily mean the birds are mourning for their lost  buddy. Rather, they're likely trying to find out if there's a threat  where the death occurred, so they can avoid it in the future.
 
In a study published recently in the journal Animal Behaviour, Swift found that American crows associate people seen handling dead crows with danger, and can be wary of feeding near such people.
Man Behind the Mask
At the start of her two-year experiment, Swift put out food at over a hundred sites where in Washington State, which attracted breeding and nesting crows.
Swift then had about 25 human volunteers don masks and asked them to  stand near the food for 30 minutes, in clear view of the crows. The  masks obscured the volunteers' facial expressions, as well as allowed a  rotating cast of people to be involved in the experiment.
Each volunteer was either holding a dead crow, standing near a dead  red-tailed hawk—a crow predator—or standing near a dead red-tailed hawk  holding the dead crow. (All the birds used in the experiment were  taxidermied.) As the control variable in the experiment—the element  that's unchanged—there was either no volunteer present or one who was  empty-handed.
Almost universally, the crows responded to seeing the people and dead  birds by “scolding”—or putting out an alert call to other crows. Of the  four situations, the hawk-and-dead-crow combination provoked the most  reaction. The crows did not react to the empty-handed control volunteer.  
The volunteers to whom the crows reacted returned to the site  periodically for six weeks, though they went empty-handed. Even so, the  crows continued to scold that person the entire length of the  experiment, and were more wary of the area for several days—suggesting  they consider people handling dead crows a threat.
In a second experiment, Swift also found the crows had a much milder  response to a masked person holding a taxidermied pigeon, indicating  "that crows are more sensitive to dead crows than to other kinds of  birds,” Swift says.
Overall, the research showed that just the inference of danger was enough to make the crows skeptical of people.

More here:

http://news.nationalgeographic.com/2015/10/151003-animals-science-crows-birds-culture-brains/