The number of elk on the National Elk Refuge in northwest Wyoming has dropped significantly in the last week as the animals undertake their annual spring migration to summer grounds.

Biologists estimated that about 1,450 elk were lingering on the refuge Sunday, according to the Jackson Hole News & Guide.

Refuge officials say many of the migrating elk have moved off the refuge to sagebrush flats north of the Gros Ventre River near Kelly as well as the Snake River corridor around Jackson Hole Airport.

Because of the exodus, a pathway bordering the refuge is expected to be open by this weekend, several days earlier than normal.

This past winter was the first in 37 years that elk and bison didn't require supplemental feeding on the refuge.