Augie researchers study bird-window collisions

Originally Posted Online: Jan. 19, 2013, 11:29 pm
Last Updated: Jan. 19, 2013, 11:40 pm
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By Anthony Watt

A group of Augustana College researchers hopes to deepen the understanding of why birds collide with closed windows.

Previous studies on the phenomenon were limited in many ways, said Augustana professor Stephen Hager, who led the college's research team.

"We've known birds have been hitting windows since we've been putting windows in buildings," he said.

The goal of his group's research was to collect more comprehensive data, so in2010, a dozen students and faculty members spent time each season monitoring 20 buildings in Moline and Rock Island.

They counted the number and types of dead birds found within about four feet of each building during daylight hours, the number and type of live birds they saw in surrounding areas, and measured the amount of window surface in square meters.

They found that only certain species were hitting windows, and most of them were about a year old or younger. They also usually were hitting buildings with lots of windows near sizable green space in which birds could live, said Dr. Hager, who has a Ph.D. in biology.

The body count was actually quite small -- only 34 birds from about 16 species, he said, adding that the group observed about 72 species of birds during its survey.

Among the dead birds, robins and doves were some of the more common, but no sparrows and pigeons were found, although live specimens were commonly observed during the research.

"That suggests there's a group of vulnerable birds," Dr. Hager said.

But the small number of dead birds found also suggests that window collisions, at least for the study area, may not be be as bad as people might think, he said.

Previous studies usually focused on one, two or a small cluster of buildings where dead birds were being observed, and often were done during the spring or fall, with little attention paid to other parts of the year, Dr. Hager said.

The local research group picked buildings at random rather than going where it knew it would find birds. It also looked at a variety of building types surrounded by varying degrees of development and green space.

The Augustana group factored in the likelihood of being able to find dead birds, and scavengers' potential effect on the targeted sites, to maintain an accurate count, he said.

Dr. Hager hopes to use the research to aid conservation efforts. His group already has used its data to create a tentative map for Rock Island and Moline, meant to predict the prevalence of bird versus window collisions in specific areas.

"This is the first map of its kind," he said.

To create it, the group mixed its data with local and federal records that helped them determine the potential amount of window surface and green space in particular areas. The researches collected information on 2,000 buildings in the study area.

The map is covered with blotches of red, orange, yellow, green and blue. Red indicated the highest risk areas, orange and yellow were next, then green and blue indicated areas of less or little risk of collisions.

There were only a few red spots on the map. Most of the rest was green and blue, though there was some orange and yellow.

Dr. Hager said the group has not yet tested the accuracy of the map's predictions with field observations. He wants to do at least one more round of research targeting what effect, if any, bird feeders might have on the prevalence of window collisions.

Those observations are planned for this year.

Dr. Hager said accurate maps of that nature could help conservationists around the country with efforts to protect birds. The hope is eventually to create a method that would allow researchers to create maps for specific areas across the United States.

The group's work has been published in PLOS ONE, an international, online scientific journal, according to an Augustana news release. The article is titled "Window Area and Development Drive Spatial Variation in Bird-Window Collisions in an Urban Landscape."

PLOS ONE's website can be found at


Local events heading

  Today is Wednesday, April 23, the 113th day of 2014. There are 252 days left in the year.

1864 — 150 years ago: Some persons are negotiating for 80 feet of ground on Illinois Street with a view of erecting four stores thereon. It would serve a better purpose if the money was invested in neat tenement houses.
1889 — 125 years ago: The Central station, car house and stables of the Moline-Rock Island Horse Railway line of the Holmes syndicate, together with 15 cars and 42 head of horses, were destroyed by fire. The loss was at $15,000.
1914 — 100 years ago: Vera Cruz, Mexico, after a day and night of resistance to American forces, gradually ceased opposition. The American forces took complete control of the city.
1939 — 75 years ago: Dr. R. Bruce Collins was reelected for a second term as president of the Lower Rock Island County Tuberculosis Association.
1964 — 50 years ago: Work is scheduled to begin this summer on construction of a new men's residence complex and an addition to the dining facilities at Westerlin Hall at Augustana College.
1989 — 25 years ago: Special Olympics competitors were triple winners at Rock Island High School Saturday. The participants vanquished the rain that fell during the competition, and some won their events; but most important, they triumphed over their own disabilities.

(More History)