White head and tail show it to be an adult, at least five years old. Lacking the species' characteristic plumage, immature birds have a darker, mottled look. The eagle isn't doing anything spectacular. It's not soaring or diving or feeding. It's simply sitting in a cottonwood, motionless except for its head, which it swivels our way as the bus slows.
Some passengers grab for binoculars or cameras, while others put faces to windows.
It's an unusual thing, to be among nine Alaskans, all intently focused on this one bird. Each of us has seen bald eagles before, many times. This is nothing new or especially exciting. But it's not the lone eagle that has us stirred up. It's what the bird portends.