(Photo courtesy of Flickr Commons/Seabamirum via the Center for Biological Diversity)

The Yellow-billed Cuckoo has been listed as threatened.

The U.S. Fish and Wildlife Service decided Thursday to add the western population of a bird to the Endangered Species List. 

The agency has listed the Yellow-Billed Cuckoo as threatened, which gives it protection under the Endangered Species Act. The bird lives in 12 western states and in Mexico and Canada, but Arizona has the largest population.

There are fewer than 500 pairs of the bird in the U.S., according to the American Bird Conservancy, which said none have been spotted in in Oregon, Washington or Montana recently.

Lots of the birds live in southern Arizona around the San Pedro River and at Cienega Creek, which conservationists also hope will be protected.

The agency said the Yellow-Billed Cuckoo’s numbers have dropped because of the severe loss of its riparian habitat, dam construction, a growth in agriculture and river flow management and protection efforts.