The Associated Press

Federal officials say they plan to decide by December whether greater sage grouse should be listed as an endangered species across much of the Rocky Mountain West, including Wyoming.

A U.S. Fish and Wildlife Service declaration that the bird is in danger of extinction could lead to new restrictions on residential, oil and gas, and agricultural development.

However, those seem unlikely until well into 2009: The process of listing the bird as endangered could take another year following December's decision on whether it is warranted, said Fish and Wildlife Service spokeswoman Diane Katzenberger.

The chicken-sized grouse, which spends much of its life on the ground, is found on the sagebrush plains of 11 states -- from Colorado to California and north to the Canadian border. Wyoming includes some of the best habitat for the bird, and officials say the population here is generally holding its own -- although energy development has reduced numbers in some areas.

The government plans next week to launch a yearlong population evaluation of the grouse after a judge in Idaho said an earlier determination that it was not endangered was "tainted."

U.S. District Judge B. Lynn Winmill in December overturned a 2005 Bush administration decision not to list the bird. Winmill said it faces "accelerating threats" from invasive weeds, fires, oil and gas development and livestock grazing.

The judge's decision came in a lawsuit filed by the Western Watersheds Project.

The sage grouse population has been declining for decades across the West, and the bird now occupies about half of its original, year-round habitat. In January 2005, the Fish and Wildlife Service estimated that there were between 100,000 and 500,000 greater sage grouse.