The term "flyway" as it applies to migratory birds has been used often lately in conjunction with concern about glass windows in the stadium under construction in downtown Minneapolis. We have heard comment about the Mississippi flyway and the birds that follow that migratory path.

The impression one could take from some of these recent references is that migratory birds follow the river bed or river valley in absolute fashion, right down the middle. That certainly would put a lot of birds over downtown Minneapolis or very close to it.

Actually, the Mississippi flyway stretches from western Minnesota to eastern Michigan. The flyway concept was developed by waterfowl biologists to designate the route used by migratory waterfowl coming from many points north. The U.S. has four such flyways — Atlantic, Mississippi, Central, and Pacific. Used these days for migratory birds of all kinds, it is a broad term.

Certainly some migrants actually do, by chance, follow the river closely. They must then negotiate a route through the city and its buildings. Birds in general, however, do not move along the flyway as through a funnel.