There's a chance—albeit a small one—that an unexpected feature of the Minnesota Vikings' beautiful new stadium will be concussions by not one but TWO species of animals.

There are two ways birds die when they collide with glass. They break their necks, and die sooner. Or, [they] suffer concussions, and, very often, die later

As has been intermittently reported since construction began on Minneapolis' U.S. Bank Stadium, animal rights activists and bird enthusiasts have been vocal about their concern over the five large glass doors that make up the building's west gate. Specifically that these large doors—which happen to be five of the largest glass doors in the world—and the glass surrounding them will be invisible to birds, reflect the background of their traditional habitat, and cause head-on collisions.

Up until now the concern mostly focused on the birds hitting the glass and dying on impact, but according to some Minnesota activists, there's a chance the birds could be flying into the glass, suffering concussions, then flying off injured to die elsewhere.

That's right: Birds, too, might be suffering concussions at the hands of the NFL.

Thankfully, so far, the Vikings' bird concussion epidemic seems unlikely. By the accounts of those who would know best, through all of the scrutiny from activist groups and concerned taxpayers and click-thirsty internet jerks like myself, to date it appears the Minnesota Vikings do not have a bird-crashing-into-their-stadium problem. As per Michele Kelm-Helgen, Chair of the Minnesota Sports Facilities Authority (MSFA):

"[The bird safety concerns] definitely came after our design was completed and done. We were very far along in that process. We're actually working with 3M—which is a local Minnesota company—that has done some films that have been used that have infrared qualities the human eye can't see it but [birds can].

First of all, we're not even sure we have a problem to be honest. I mean, [birds hitting the glass] is not something that really has been documented. But we're going to look at that and if we do [have a problem], we have some solutions that can be done after the fact.

Our whole design was centered around this clear [design]—you can see in, you can see out, you're connected to the city. The fritted glass that they were asking us to look [at], not only was the design basically done but it really changed the whole approach and the design intent of the building. So what we wanted to do is preserve that transparency but at the same time if we do have a problem, I think we have a solution that can be done after the fact."

It's easy to see why Kelm-Helgen is so protective of the original concept—the illuminating effect the glass doors and clear ETFE (ethene-co-tetrafluoroethene) roof give the stadium's interior is perhaps the structure's defining feature.

First of all, we're not even sure we have a problem to be honest. ... But we're going to look at that and if we do, we have some solutions

I know this because the Vikings allowed me to personally tour the stadium, which opens in August, to see things for myself. The place is spectacular—on-the-field suites, multiple lounges including a fantasy football-specific lounge, a literal Viking ship out front with a mast that's also a projection screen, best-in-class WiFi...all the bells and whistles Viking first down horns you'd expect from a $1.1 billion building. It's amazing. If the original glass was replaced by fritted glass (a change the AP reported would cost more than $60 million), it would certainly impact the building's intended feel.

Image via Minnesota Vikings

As for the 3M film solution? Well, with Kelm-Helgen also saying the Vikings "aren't there yet" and "aren't sure yet" when it comes to pricing out such a large-scale infrared film installation, it's safe to say that's not something U.S. Bank Stadium will preemptively pay for. Though perhaps those around the team should be credited for finding a workable future solution while presently there remains little evidence of damage to local birds.

But—as Jim Williams wrote in a blog for the Minneapolis Star Tribune—perhaps bird concussions are the reason there is no evidence (Read: dead birds):

There are two ways birds die when they collide with glass. They break their necks, and die sooner. Or, the suffer concussions, and, very often, die later, after flying away. I’ll bet the Minnesota Vikings football team doesn’t know about the concussion part. 

You’d think that the Vikings, of all people in town, would understand concussions.

Shots fired, indeed. Williams goes on to say using bird-safe glass would only cost $1 million (a far cry from the reported $60 million) and calls the stadium "a glass killing zone for migrant birds." Which seems a bit extreme, especially considering the more measured stance the Minnesota Audubon Society took when I asked them to comment:

The MSFA, the Vikings, 3M and the Audubon Society continue to work together on preliminary tests of potential 3M bird-safe window film solutions. These efforts have been positive and collaborative, and we hope to have more information to share in the near future.

Still, measured or not, with somewhere between 365 million and 988 million birds killed every year in the U.S. alone from crashing into man-made structures according to 2014 research by the Smithsonian Migratory Bird Center and U.S. Fish and Wildlife Service, the bird safety debate is not one that should be taken lightly. As preposterous as it sounds, that's a million birds a DAY dying in the United States from hitting structures on the low end, and nearly a BILLION a year on the high end. That's a lot of dead birds.

Time will tell if U.S. Bank Stadium indeed is part of this nationwide bird collision problem. Money and technology will dictate how the organization responds to such a problem, if it exists.