Wildlife experts say they are treating more injured snowy owls than usual this year in Minnesota.

The owls have flown thousands of miles from the Arctic and are being spotted in higher numbers in parts of the northern U.S., including around the Great Lakes, to the delight of local bird watchers. But that also translates into an uptick in the number of injured birds, Minnesota Public Radio reported .

So far this season, the Gabbert Raptor Center at the University of Minnesota has treated 33 snowy owls “and that is significantly above normal,” said Julia Ponder, a veterinarian and the center’s executive director.

Some of the owls had died by the time they arrived at the center, about half from starvation. The others died from injuries. Two are still being treated.

The only owl that has been treated and released so far was found trapped in an industrial coffee roaster after falling down a chimney at a Duluth coffee roasting company. The bird was released near Duluth earlier this month, Ponder said.

“He flew beautifully, he left and went straight back to the wild. Perched in a tree,” Ponder said.

Experts are crediting the higher number of snowy owls to a robust food source of lemmings, which are small Arctic rodents. That enables more owlets to survive, and when they grow up, they have to leave to find their own hunting territories. Some make their way to the northern U.S.

“They can have eight, nine, 10, 11, 12 babies in a single clutch of eggs,” said Laura Erickson, a Duluth bird enthusiast and author.

She noted that the increased number of visiting birds can attract big crowds of people, “and so it’s important for people not to get too close. It’s very enticing, but we have some ethical responsibilities.”

Experts said getting too close can stress the animals.