Crows Are Bandits, But Know Thier Own Kind

Robinette focused on one bird for five minutes, logging every activity, and then she moved on to another bird, a process she repeated thousands of times. The beach turned out to be a perfect place for observing the birds, because the forest was some distance away, allowing a clear view of the birds' activities.

Here's what she found:

Some of the birds were honest as Abe, but most were real bandits.

"We discovered that some of the birds never scrounge, and never steal," James Ha says. "They walk along and they find their own food. They may have it stolen from them, but they never steal."

But the bandits had a very different lifestyle, stealing roughly 65 percent of the time.

"We never had a bird that lived only by stealing, but we had birds that spent most of their time trying to steal," he adds. "It's pretty much how they are making their living."

It remains a mystery why some of the birds were honest while other members of the flock were corrupt.

"We have no idea" why that should be the case, Ha says.

"So we have tried to take it to a different level," he adds. "It's the most controversial."

Knowing Their Own Kind

Robinette set out to identify genetic markers in the blood samples taken from the crows in an effort to determine the relationship among the birds. Those markers, she hoped, would tell her if crows were stealing from their immediate relatives, or from their more distant relatives in the flock.

What she learned was quite surprising, and potentially of major importance, if the early findings are correct.

The bandits engaged in two types of theft — passive and aggressive. In some cases, the thief just walked casually up to a bird with a morsel, and the victim dropped the food and walked away. In other cases, however, the bandit squawked and chased its victim until the bird dropped the food.

The crows tended to be passive when stealing from birds to whom they were closely related, and aggressive toward their non-relatives.

"That seems to imply that they can recognize relatives from non-relatives," Ha says.

That would suggest that the birds are engaged in very complex social behavior patterns indeed.

And it would add another footnote to the legacy of the family Corvidae, which includes crows, ravens, jays and magpies. According to Kevin McGowan, a Corvid expert at the Cornell Laboratory of Ornithology, these birds have rivaled monkeys in some psychological tests. Ravens and magpies are believed to be able to count up to seven, and the crows of the Northwest drop shellfish onto hard surfaces to break them.

Perhaps most intriguing, McGowan says, the New Caledonian crow of the South Pacific makes complicated tools out of leaves and twigs to probe holes in trees for food. Then it stores the tools for later use.

The crows studied by the University of Washington team didn't go that far, but it turns out the crows weren't the only ones engaged in complex behaviorial patterns on the beaches north of Seattle over the past few years. Robinette and Ha were married last March.

Lee Dye’s column appears weekly on A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

  • 1
  • |
  • 2
Join the Discussion
blog comments powered by Disqus
You Might Also Like...