Bird watchers are concerned that U.S. Bank Stadium's signature glass facades will confuse birds, causing them to collide and die. Of particular concern is the stadium's proximity to the Mississippi River migratory flyway.

Three years and $300,000.

That's what the Minnesota Sports Facilities Authority (MSFA) proposes for the duration and cost of a study to determine whether the glassy new $1.1 billion U.S. Bank Stadium turns out to be a deadly draw for migratory birds.

After 30 months of construction, the ribbon-cutting for the new stadium is a week away. For the past couple of years, environmentalists concerned about bird fatalities have unfailingly attended MSFA meetings, using brief public comment periods to voice their worries.

The bird advocates are concerned that the building's 200,000 square feet of glass will confuse birds, causing them to collide and die. Of particular concern is the stadium's proximity to the Mississippi River migratory flyway.

On Friday's MSFA agenda, there is a one-paragraph item called a “memorandum of understanding with the National Audubon Society.”

According to the agenda, the Vikings and the MSFA will pay $150,000 each “to design a collaborative, scientific program to design, research, observe, monitor, analyze, and assess the potential impact of the stadium on bird mortality due to bird collisions.”

Lester Bagley, Vikings vice president, said workers at the stadium have seen no impact on birds so far. “But we want to be good community partners, and this is an important issue,” he said.