U.S. wildlife managers proposed Thursday to set aside a vast area across seven Western states as habitat critical to the survival of a rare songbird that migrates each year from Central and South America to its breeding grounds in Mexico and the U.S. The U.S. Fish and Wildlife Service made public its recommendation for the western yellow-billed cuckoo in a federal notice. Each spring and fall, the cuckoo uses river corridors as routes to travel between its wintering and breeding grounds.