Released: March 15, 2004

‘Killer’ Robins Simply Nesting

LAWRENCE, Kan. – Red-breasted robins – those sweet-looking harbingers of spring – are now viciously attacking windows, gazing balls and anything else reflective in the landscape, reviving memories of Alfred Hitchcock’s 1963 thriller “The Birds.”

“What may look like killer robins is just another example of how crazy some animals can seem when they enter their reproductive season. While they’re nesting, birds’ territorial instinct becomes more powerful than their urge to eat or sleep. Few things can make them stop attacking reflected images of themselves,” said Bruce Chladny, horticulturist with Kansas State University Research and Extension.

Defending territory is how animals ensure their offspring will have enough food, Chladny said. Male and female robins both do their best to keep same-sex adults outside of their territorial boundaries.

Unfortunately, birds can see well. For example, the faint reflection on a window that’s backed by a closed curtain is still evident to them. What’s not evident, however, is that they’re seeing themselves.

“It’s one of those funny-sad things,” the horticulturist said, outlining this as the typical scenario:

* A robin notices its own reflection within its territory and gets agitated.

* Trying to frighten the interloper away, it raises its head feathers and takes a dominant stance.

* That doesn’t make the reflected robin leave – as a robin would normally. Instead, the reflected robin also raises its head feathers and assumes an equally dominant stance.

* Worried, the real robin leaves. If male, he goes to his favorite song perch to sing. And, when he hears no responding song, he becomes more certain the territory is really his. If female, she goes back to daily activities, but keeps watching for intruders. When none challenge her, she gains confidence, too.

* The robin returns, finds the reflection again and gets more agitated. But, so does the reflection.

* The robin flies in, to chase the intruder away. The reflection flies in, in exactly the same way.

* The robin becomes more and more determined to succeed.

“When the real bird finally gets desperate enough to fly into the reflective surface, it can leave feathers, mud, droppings and even blood behind,” Chladny said. “That can not only create quite a mess but also make you feel pretty guilty for having inadvertently helped create the situation with something shiny.”

The only sure remedy for the situation is to remove the reflective object. Usually, however, that’s practical only with such landscape ornaments as mirrors and reflecting balls.

“You can put them back when the baby birds hatch. A parent bird gets so busy tending to the babies’ feeding and care that it has to stop worrying about some phantom image of itself,” Chladny said.

Another effective remedy is to tape paper or cardboard over the reflecting surface. A complete job of “soaping” the surface can work, as well.

“A rubber snake or plastic owl sometimes does the job, but birds often figure out within days that those things are fake,” Cladney said. “With windows, though, you also can try hanging helium-filled silver Mylar balloons, tied to 2- or 3-foot lengths of string and attached so they float at just about the level the robin is focused on. For some reason, birds seem to fear helium balloons – perhaps because nothing they encounter in the natural world ‘falls up,’ so the balloons’ movements seem very unpredictable.”

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Kathleen Ward
kward@oznet.ksu.edu
K-State Research& Extension News