September 17, 2008

Hungry Birds = Bad Neighbors

So, I promise a real BOTW (the northern pintail) is coming soon. I don't have any excuses for not posting it besides just really getting into Fall TV and suffering from a dysfunctional DVR. (Love the CW, by the way, and I don't care if that puts me in the company of 13-year-old girls.)

Anyway, I noticed this news story on Live Science today and thought it was pretty interesting. I'm not sure about using the word "murder" in the headline (can animals really murder each other?), but it sounds like food shortages can bring out some pretty brutal behavior in bird parents. Although, history tells us it gets nearly as nasty when humans are under similar circumstances.

Food Shortages Drive Birds to Murder Chicks

by LiveScience staff
Photo credit: Kate Ashbrook

Adult seabirds in Scotland have launched brutal attacks on chicks in nearby nests, sometimes pecking to death the fledglings or just flinging them from cliff ledges. The ferocious attacks were documented in a study announced today.

"The attacks were brutal and usually involved more than one adult as chicks fled from the initial attacking neighbor," said lead researcher Kate Ashbrook of the University of Leeds in England.

The cause of the peck attacks can be traced to food shortages in the area where the common guillemots live, the study scientists suggest. Common guillemots (Uria aalge) are attentive parents, rearing just one chick during the breeding season.

They spend most of their time at sea except during the breeding season when the adults relocate to rocky coastal cliffs or offshore islands. On land, the white-bellied birds stand upright like penguins and reach a length of about 16 inches (43 centimeters).

Since chicks are vulnerable to attacks from predatory gulls, guillemot parents rarely leave their single chick unattended, taking turns heading out to find food. However, a decline in prey in recent years has forced both parents to search for food at the same time.

Ashbrook and her colleagues focused on a large established colony of guillemots that inhabit the Isle of May in Scotland. They reported almost half of all chicks were unattended at some point during the day. And the researchers observed hundreds of adult guillemots attacking such nests. The attacks often involved repeated jabs to the head and body, the researchers noted.

And even though food shortages sparked the attacks, the researchers said the guillemots clearly were not attacking the chicks for food, but rather as acts of aggression.

"More than two thirds of all documented chick deaths in the sample area were caused by attacks from neighboring parents," Ashbrook said. "Yet this particular colony has been monitored for almost thirty years, and in that time chick attacks have been very rare occurrences."

The findings, published online today in the journal Biology Letters, indicate that social harmony, as can be the case in such long-established colonies, can break down when conditions get tough.

The study also highlights a parental dilemma in the seabirds when starvation looms: They must choose between both parents foraging for food and possibly finding enough to feed their family or keeping one parental in the nest even if it means less food for the chick, the researchers say.



The mean Amy said...

There are a few people at work I'd like to peck to death and throw off a cliff ledge....I think they know who they are and I hope are getting ready for a pecking of their lives....I'm sharpening my beak as we speak...just kidding! Mostly.

Kelly Branan said...

I think LiveScience could have explored the idea that this is a way the birds ensure survival of their species. If there isn't enough food to go around they simply reduce the number of hungry mouths to feed. The offspring of the attacking birds will be the ones that survive causing, through this natural selection process, the species to become more aggressive, and more protective of its young.

Or maybe the older generation of birds doesn't have as much patience with snot-nosed chicks being left alone to bother them and thier kids.

Patrick said...

I think the title should have been "When Guilemot Parents Attack!" Then it could also be turned into a FOX special!

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