A new study finds U.S. Bank Stadium and three high-rise buildings account for a high proportion of bird fatalities among 21 buildings surveyed in downtown Minneapolis.

The Star Tribune reports the study in PLOS One found the stadium and three unidentified towers were involved in 74% of collisions and 68% of fatalities among the buildings studied.

Data from two migratory seasons indicate around 111 birds died annually in collisions with the stadium.
The Minnesota Vikings and the stadium authority paid for the study, which was promoted by conservationists’ concerns about birds following the Mississippi River corridor colliding with the stadium’s glass walls.

Jerry Bahls of the Audubon Chapter of Minneapolis says the study appears to confirm their concerns and they want the Vikings and stadium authority to address the problem.