They are the heaviest owls in North America, weighing 4 pounds on average. Females can weigh as much as 6.5 pounds. They are nearly 2 feet in length and have a wingspan of over 4 feet, on average.

Park rangers keep their eyes on the owls. They make sure everyone follows the rules: Keep 150 feet away (half a football field); do not walk on the dunes or try to get a rise out of the birds.