Sure, Mark MarÂtell had heard of birds crashÂing into man-made strucÂtures, such as skyÂscrapÂers, wireÂless comÂmuÂniÂcaÂtion towers and wind turÂbines — ofÂten faÂtalÂly.
But bridgÂes?
"It might just be someÂthing about the height of the bridge, but I don't know," said MarÂtell, diÂrecÂtor of bird conÂserÂvaÂtion for Audubon Minnesota, afÂter hearÂing reÂports that miÂgraÂtory birds were flyÂing into the new Hwy. 61 Hastings bridge or beÂcomÂing enÂtanÂgled in the cables holdÂing up the $130 milÂlion span that conÂnects the hisÂtorÂic river town to Washington County. But while enÂvirÂonÂmentÂalÂists and bird exÂperts have spent years studyÂing how buildÂings in urÂban areas came to be such proÂlifÂic bird killÂers, little such reÂsearch has been done on bridgÂes, MarÂtell said.
He hopes a new study, comÂmisÂsioned by the state Department of Transportation, will change that.
The study will be conÂducted amid conÂcerns that birds flyÂing back from their winÂterÂing grounds in Central and South America may be killed or injured by flyÂing into the bridge, which crossÂes the aviÂan exÂpressÂway that is the MisÂsisÂsipÂpi River.
More than 300 speÂcies of birds — "milÂlions, if not bilÂlions" — fly along the rivÂer to and from their winÂterÂing grounds, said the park servÂice's Paul Labovitz, who serves as superÂinÂtendÂent of the MisÂsisÂsipÂpi River National River and RecÂreÂaÂtion Area.
"I watched a flight of peliÂcans one sumÂmer day flyÂing over that took 15 minÂutes to pass over me," Labovitz said last week. "So the numÂbers are stagÂgerÂing."
MnDOT ofÂfiÂcials plan to hire an enÂviÂronÂmenÂtal firm to study what makes bridgÂes a threat to birds, which they hope will serve as a temÂplate for getÂting arÂchiÂtects to buy into bird-friendÂly deÂsigns in the fuÂture.
"At least in the case of buildÂings, we know that there are some things that can be done to reÂduce it," Martell said.
MarÂtell pointÂed out that the National Park Service had signed off on the 545-foot tied-arch bridge — ofÂfiÂcials reÂjectÂed a cable-stayed deÂsign in part beÂcause it might pose a threat to miÂgratÂing birds, he said — on the conÂdiÂtion that MnDOT underÂtake anÂothÂer study to betÂter underÂstand the probÂlem of bird strikes on bridgÂes.
The study could cost up to $100,000, MarÂtell said.
"The botÂtom line is we just don't know very much about it, so this parks servÂice study is someÂthing that inÂterÂests us and many othÂers," MarÂtell said.
A MnDOT spokesÂwomÂan did not reÂturn calls for comÂment.
"It's a conÂverÂsaÂtion that's been going for acÂtuÂalÂly a couÂple of years, but we're getÂting to the point where we're acÂtuÂalÂly tryÂing to frame what the study's going to be," Labovitz said.
"We didn't have the inÂforÂmaÂtion to inÂform this parÂticÂuÂlar bridge deÂsign," Labovitz said," but we were hopÂing that this inÂforÂmaÂtion would inÂform fuÂture proÂjects."
Audubon Minnesota has partÂnered with the Building OwnÂers and ManÂagÂers Association (BOMA), a trade group whose memÂbers repÂreÂsent many high-rise buildÂings in the metÂro area, on a program called "Lights Out" that enÂcourÂagÂes buildÂing ownÂers to reÂduce lightÂing durÂing spring and fall miÂgraÂtions "in an efÂfort to reÂduce buildÂing strikes." So far, ofÂfiÂcials said, the program has enÂlisted nearÂly 60 tall buildÂings, inÂcludÂing the Wells Fargo Center and the IDS Center.
SomeÂthing simÂiÂlar should be tried on the Hastings bridge, MarÂtell sugÂgestÂed, whose lights could be dimÂmed to avoid conÂfusÂing night-miÂgratÂing birds, who naviÂgate using the moon and stars and are ofÂten atÂtractÂed by the glow of lightÂing from buildÂings.
The U.S. Fish & WildÂlife Service esÂtiÂmates that at least 97 milÂlion and as many as 976 milÂlion birds are killed anÂnuÂalÂly in the UnitÂed States when they crash into buildÂings. There are no figÂures yet on the numÂber of birds killed when they fly into othÂer man-made strucÂtures.
He conÂtinued: "You have to wonÂder in 2014 why we don't know more about this topÂic."
Libor Jany • 651-925-5033
Twitter:@StribJany