Nesting in this general zone, in rocky cliffs and canyons, are the GOLDEN EAGLE (seen every summer); the CANYON WREN (its characteristic “laughing” song is often heard during May and June); and the WHITE-THROATED SWIFT (which comes in early May to nest in crannies in the cliffs at the very east edge of the park, and leaves in June). Some birds commonly nest in lodgepole and aspen forests, from about 8,500 feet upward. They include the WESTERN WOOD PEWEE, with a dark gray back, dull gray underparts, and two white bars on the long wings; the WARBLING VIREO, a migrant that arrives in a “wave” late in May; the LINCOLN’S SPARROW, streaked, with a short tail, which spends only 2 months in the park; the RUBY-CROWNED KINGLET, which appears suddenly in late April and fills the forests with its song during June; the showy AUDUBON’S WARBLER, with its fire-bright yellow spots and white wing patches; and the HERMIT THRUSH, whose songs ring through the lodgepole and spruce-fir forests and along the streams in July. In the spruce-fir forest, nesting birds you may expect to see include the PINE GROSBEAK, a large finch, the male of which has a rich rose-red head and breast; and the BROWN CREEPER, named for its habit of creeping up tree trunks. Thickets near treeline are the nesting area of the WHITE-CROWNED SPARROW, a bird with strikingly black-and-white striped crown. It is as much at home above treeline as below, usually ready to scold all hikers who invade its territory. The WILSON’S WARBLER, with yellow body and black cap, nests in the willows at this altitude, but leaves the heights in August and returns in May. Above the forests, on the wind-swept tundra, are some of the most interesting birds of the park. Here WHITE-TAILED PTARMIGANS spend the entire year. These alpine grouse, mottled-brown in summer, become pure white in midwinter. They assemble in small flocks in September to spend the winter together, but disperse during May and June for courtship and breeding. Nesting ptarmigans have been seen close by the busy Trail Ridge Road. Depending upon their natural camouflage for protection, they seldom show alarm when closely approached. Ornithologists travel far to see BROWN-CAPPED ROSY FINCHES, which breed only on the high mountains of Colorado and probably northern New Mexico. Nesting in cliffs above treeline in summer, they band together in autumn to descend into the ponderosa forests for the winter. A third common bird of the tundra is the WATER PIPIT, a small ground bird, whose white-bordered tail is almost constantly in wagging motion. Pipits have an interesting courtship flight, and during midsummer are seen only above treeline, where they nest. By late August they descend to lower altitudes, not to return until June.