This winter looks like it may be a good year for observing snowy owls (Nyctea scandiaca) in many of the northern lower 48. We seem to be having a snowy owl irruption.
Snowy owls nest in the treeless Arctic tundra, but during an irruption, some will need to head south into Southern Canada and the northern USA. An irruption occurs when the owls lay large clutches of eggs in response to high populations of their prey, i.e., lemmings, voles, ptarmigan, etc. When the summer ends and prey is not so readily available, some of the raptors will head south looking for food.
This year the Wisconsin DNR is reporting a large number of the raptors are juveniles. Unfortunately the mortality rate for young snowy owls is pretty high — not typically from starvation, however, but from collisions with vehicles and fences, electrocution on power lines, and poisoning from rodenticides.
Airports are particularly troublesome for the raptors since their flat, treeless expanses remind them of the tundra, but an encounter with an airplane will not yield the same results as with a ptarmigan.
If you happen to observe a snowy owl, don’t try to get too near it. Stay at least 100 yards away. Use a spotting scope or binoculars to watch. Getting too close stresses the birds. If the bird looks at you or flushes from his perch, you’re too close.
See also the snowy owl tracking program Project SNOWstorm.