Boreal and Great Gray owls, the two species that have made birding in Minnesota particularly exciting this winter, are in retreat. Most seem to have left the area, heading north to their usual territories. Additional birds are being found dead, thought to be victims of starvation. The birds came south to find food. These owls hunt rodents that move beneath the snow cover. The crusty snow we have now has made hunting difficult. The birds can sense the mice, shrews, and voles, but can't break through the crust to make a capture. Two readers were fortunate enough to have Boreal Owls in their yards. The first photo comes from Will Stenberg of Duluth. The owl has a mouse in its grip. This might be the best Boreal Owl photo I've seen: owl, snow, prey. Wish I had taken it. The second comes from Sadie Ellingson of Elk River, another fine photo. Ms. Ellingson's bird spent at least 12 hours perched in a tree just outside her kitchen window. She first saw the bird at 7 o'clock in the morning, and watched it leave as the sun was setting.