BISMARCK, N.D. (AP) – The U.S. Fish and Wildlife Service says an aerial count of American white pelicans nesting in North Dakota doesn’t give a clear picture of the number of the big-billed birds.

The nesting colony at Chase Lake National Wildlife Refuge is the largest in North America. Acting Refuge Manager Drew Williams says an aerial survey last month was done in the afternoon and counted only 12,000 birds.

Williams says most adult birds were probably feasting on fish and salamanders from lakes in the area when the photo was taken.

Williams says biologists believe the number of adults at the refuge is probably down only slightly from last year’s count of 29,000 birds.

The pelicans normally arrive at the refuge north of Medina in early April and stay through September.