TOPEKA, Kan. (AP) — A new aerial survey of Kansas has revealed new breeding grounds for the lesser prairie chicken as the bird’s habitat appears to be moving north.

Lesser prairie chickens have been considered a candidate under the Endangered Species Act since 1998 as a threatened or endangered species.

The Kansas Department of Wildlife, Parks and Tourism says the survey was part of a five-state project to determine the numbers of birds in the region and their breeding grounds. The survey was conducted ahead of the release of a proposed rule by the U.S. Department of Wildlife and Parks on the status of the birds.

The survey suggests the lesser prairie chickens are expanding northward as habitat improves. Their numbers have been increasing in Kansas over the past 15 years.