Concerns that the massive, glassy new Vikings stadium in downtown Minneapolis will kill thousands of birds cruising into its giant windows have found sympathies at City Hall.

The City Council, which engaged in a fractious debate over the stadium's construction in 2012, will consider Friday whether to formally support an effort to have the facility fitted with bird-safe glass. The Washington-based American Bird Conservancy also joined the effort Wednesday, asking for a meeting with the National Football League.

The Vikings have previously rebuffed calls from Audubon Minnesota, a branch of the National Audubon Society, to shell out an extra $1.1 million for the specially glazed glass at the stadium, expected to cost nearly $1 billion altogether.

A resolution drafted by five council members seeks to apply more pressure, noting that migrating birds frequently use the Mississippi River as a navigational aid and make the metro area their stopover point in the spring and fall. The resolution was authored by Council Members Linea Palmisano, Cam Gordon, Alondra Cano, Lisa Bender and Andrew Johnson.

"The city of Minneapolis is contributing approximately $150 million in local sales tax revenue to building the stadium, and the interests of the people of Minneapolis should be honored in the design of the stadium," the resolution says.

Leaders with the Minnesota Sports Facilities Authority, which is overseeing the stadium's construction, said a year ago that the facility would turn off lights at night once the facility is built to help prevent bird collisions. The council resolution states that the lighting is distinct from the calls for different glass, however.

The city's stadium implementation committee and the Minnesota Department of Natural Resources have both outlined the need to mitigate bird deaths in the stadium's design.

"Ensuring that the stadium is bird-safe will improve visitor experience and be good for the Vikings and Minnesota Sports Facilities Authority in the long run," the resolution says.

Palmisano said that the city approved the stadium subject to the conditions of an implementation committee, which said the design should be bird-safe.

"I hope this starts the conversation in the city that we're asking the Vikings to honor the agreement," Palmisano said.

She added: "Ironically, a thousand years ago, the real Vikings made use of birds for helping with navigation."

The City Council will discuss the resolution at its meeting Friday.

Separately, the American Bird Conservancy said in a letter to the NFL that the large glass wall "will cause the avoidable and unnecessary deaths of birds legally protected by federal law."

"Bird collision mortality is certainly a contributing factor to the unfortunate reality that we now have over 200 species of birds suffering population declines or in serious trouble," Christine Sheppard, who runs the bird collisions campaign for the group, said in a statement.

For more detailed information on the types of birds typically involved in building crashes, the Audubon Society's "Project BirdSafe" has answers at http://mn.audubon.org/project-birdsafe.

Eric Roper • 612-673-1732

Twitter: @StribRoper