While snowy owls spend most of their lives near the Arctic, there are times when they might venture south of the Canadian border.

“Snowy owls occasionally make their way into Pennsylvania, especially during irruption years,” according to Hawk Mountain Sanctuary research biologist Dr. Rebecca McCabe.

An irruption occurs when large numbers of birds move beyond their typical range.

“For example, this winter (2024-25), eBird reports show a snowy owl observed in Philadelphia and one up near Lake Erie in northwestern Pennsylvania,” McCabe said.

McCabe is a participant of Project SNOWstorm, a crowdfunded snowy owl research project that tracks the owls and shares other information.

According to Project SNOWstorm, an irruption was once thought to be caused by hungry owls flying south in search of food.

Instead, “Winter irruptions are usually caused by an abundance of food during the previous summer. Lemmings — small rodents that make up most of the owls’ summer diet — regularly fluctuate in numbers. A boom of lemmings produces a boom of healthy owl chicks migrating south,” Project SNOWstorm notes.

McCabe said that anyone who sees a snowy owl should not approach it. It’s recommended to observe the owls from a distance or from the inside of a vehicle.

They should also never feed an owl. Owls might begin to associate people with food, and approach humans who harm them out of fear, malice or by accident.

The U.S. Fish and Wildlife Service shares the following about snowy owls:

• Bristles on their beaks help them sense nearby objects.

• Needing insulation from Arctic temperatures, snowy owls have many feathers, which makes them one of the heaviest owl species in North America.

• Their feet are covered with feathers to provide insulation in the cold Arctic climate.

• Snowy owls will eat a variety of food including lemmings, arctic hares, mice, ducks and seabirds. They swallow small prey whole.

• Females remain with the young. Males bring food and females feed it to the owlets.

• Their wingspan averages 4 to 5 feet.

• Male snowy owls are almost completely white, while females are white with dark bars on white plumage.

• Unlike most owls that are nocturnal, snowy owls are diurnal. The Arctic summer forces snowy owls to hunt by daylight.