Thanks to the Trilobites feature on the New York Times website for this story of collaborative friendliness between species:
Chances are that’s a shy elk looking back at a bold magpie, in the photograph above.
They get along, so to speak, because the elk needs grooming and the magpie is looking for dinner. But they may have never entered into this partnership if it weren’t for their particular personalities, suggests a study published Wednesday in Biology Letters.
Let’s start with the elk. In Canada’s western province of Alberta, they’ve been acting strange. Some have quit migrating, opting to hang around towns with humans who protect them from predators like wolves. Others still migrate.
As a doctoral student at the University of Alberta, Robert Found, now a wildlife biologist for Parks Canada, discovered over years of observing their personalities that bold elk stayed, while shy elk migrated. But he noticed something else in the process of completing his research: As elk laid down to rest at the end of the day, magpies approached.
There appeared to be a pattern: elk of some personality types aggressively rejected magpies. Others didn’t. “Sometimes the magpies will walk around right on the head and the face of the elk,” Dr. Found said.
Scientists define animal personality by an individual animal’s behavior. It’s predictable, but also varies from others in a group. Dr. Found created a bold-shy scale for elk, measuring how close they allowed him to get, where elk positioned themselves within the group, which elk fought other elk, which ones won, how long elk spent monitoring for predators and their willingness to approach unfamiliar objects like old tires, skis and a bike. He also noted which elk accepted magpies.
To study the magpies, he attracted the birds to 20 experimental sites with peanuts on tree stumps. During more than 20 separate trials with different magpies, he judged each bird’s behavior relative to the other magpies in a trial. Like the elk, he measured flight response, social structure and willingness to approach items they hadn’t previously encountered (a bike decorated with a boa and Christmas ornaments). He also noted who landed on a faux-elk that offered dog food rather than ticks (a previous study showed magpies liked dog food as much as ticks)…
Read the whole story here.