Real angry birds 'flip the bird' before a fight

Jan 29, 2013
sparrow

Male sparrows are capable of fighting to the death. But a new study shows that they often wave their wings wildly first in an attempt to avoid a dangerous brawl.

"For , wing waves are like flipping the bird or saying 'put up your dukes. I'm ready to fight,' " said Duke biologist Rindy Anderson.

Male swamp sparrows use wing waves as an aggressive signal to defend their territories and mates from intruding males, Anderson said. The findings also are a first step toward understanding how the birds use a combination of and songs to communicate with other males. Anderson and her colleagues published the results online Jan. 28 in the journal .

Scientists had assumed the sparrows' wing-waving behavior was a signal intended for other males, but testing the observations was difficult, Anderson said. So she and her co-author, former Duke engineering David Piech ('12), built a miniature computer and some robotics, which the team then stuffed into the of a deceased bird. The result was a 'robosparrow' that looked just like a male swamp sparrow, which could flip its wings just like a live male.

This video is not supported by your browser at this time.

Anderson took the wing-waving robosparrow to a swamp sparrow in Pennsylvania and placed it in the territories of live males. The robotic bird "sang" songs using a nearby sound system to let the birds know he was intruding, while Anderson and her colleagues crouched in the swampy grasses and watched the live birds' responses. She also performed the tests with a stuffed sparrow that stayed stationary and one that twisted from side to side. These tests showed that wing waves combined with song are more potent than song on its own, and that wing waves in particular, not just any movement, evoked from live birds.

The live birds responded most aggressively to the invading, wing-waving robotic sparrow, which Anderson said she expected. "What I didn't expect to see was that the birds would give strikingly similar aggressive wing-wave signals to the three types of invaders," she said. That means that if a bird wing-waved five times to the stationary stuffed bird, he would also wing-wave five times to the wing-waving robot.

Anderson had hypothesized that the defending birds would match the signals of the intruding robots, but her team's results suggest that the males are more individualistic and consistent in the level of aggressiveness that they want to signal, she said.

"That response makes sense, in retrospect, since attacks can be devastating," Anderson said. Because of the risk, the real males may only want to signal a certain level of aggression to see if they could scare off an intruder without the conflict coming to a fight and possible death.

Still, the risk of severe injury or death didn't keep the studly males from swooping in and clawing at the robotic intruder, whether it wing-waved or not. "It's high stakes for these little birds. They only live a couple of years, and most only breed once a year, so owning a territory and having a female is high currency," Anderson said.

She and her team had planned to test how the sparrows use wing waves combined with a characteristic twitter called soft-song to show aggression and fend off competition. But the experiment may be on hold indefinitely because robosparrow's motor seems to be burned out, and its head was ripped off in an attack, a true fight to the death.

Explore further: "Light pollution" may affect love lives of birds in the Viennese Forests

More information: "Male response to an aggressive visual signal, the wing-wave display, in swamp sparrows," Anderson et. al. (2013). Behavioral Ecology and Sociobiology. Online ahead of print. DOI: 10.1007/s00265-013-1478-9

Related Stories

Bird song-sharing like verbal sparring

Aug 10, 2011

While singing the same songs as your neighbours may sound harmonious, research conducted at Queen's University Biological Station (QUBS) suggests that song-sharing amongst song sparrow populations is actually ...

It takes two to tutor a sparrow

Oct 21, 2009

(PhysOrg.com) -- It may take a village to raise a child, and apparently it takes at least two adult birds to teach a young song sparrow how and what to sing.

It's a bird, it's a plane, it's a robot bird (w/ video)

Mar 29, 2011

(PhysOrg.com) -- The great thing about robots is that they come in all shapes and sizes. Of course, that is also one of the creepiest things about robots too. You never know what is going to be a robot these ...

Recommended for you

Rising temperatures can be hard on dogs

12 hours ago

The "dog days of summer" are here, but don't let the phrase fool you. This hot time of year can be dangerous for your pup, says a Kansas State University veterinarian.

Monkeys fear big cats less, eat more, with humans around

15 hours ago

Some Monkeys in South Africa have been found to regard field scientists as human shields against predators and why not if the alternative is death by leopard? The researchers found the monkeys felt far safer ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Jonseer
1 / 5 (1) Jan 29, 2013
So now I know what all the commotion has been about in my my fire leaf bush in front of the house. The sparrows are having regular "to the death" fights among the branches. It explains the occasional dead sparrow I find underneath it. LOL