Waterfowl typically arrive when the ice vanishes in April. The peak migration occurs in late May when one can observe 5,000 or more ducks on any given day. Canada geese begin to nest on the Refuge in April and ducks in late May, but peaking in mid-June. The Refuge produces about 3,000 ducklings and from 100 to 250 goslings each year. Arapaho is the second largest producer of waterfowl in the state of Colorado.
Primary upland nesting species include mallard, pintail, gadwall, and American wigeon. A number of diving ducks, including the lesser scaup, ruddy, and redhead nest on the larger ponds and adjacent wet meadows. Most species can be observed during the entire summer season. In late September or early October fall migration peaks when up to 8,000 waterfowl may be on the Refuge.
Refuge wetlands also attract numerous marsh, shore, and water birds. Sora and Virginia rails - shy, secretive birds - are abundant, but seldom seen. More visible birds such as eared and pied-billed grebe, Wilson's phalarope, American avocet, willet, sandpipers, yellowlegs, and dowitchers are a common sight on the Refuge. Other less common species include great blue heron, black-crowned night heron, American bittern, and white-faced ibis. The sagebrush steppe upland harbors sage-grouse year around, but the birds are most visible in the summer when they have broods and are traveling from the cover of the sagebrush to the meadows to forage on succulent forbs and nutrient-rich invertebrates. There are no leks for public viewing on Arapaho NWR.Raptors such as northern harriers, Swainson's hawks, rough-legged hawks, golden eagles, American kestrels, and prairie falcons circle the skies above the Refuge in search of food. Short-eared owls and great horned owls can also be observed here. Raptor prey includes Wyoming ground squirrel, white-tailed prairie dog, white-tailed jackrabbit, mountain cottontail, mice, shrews and voles. Songbirds that can be seen year-round on the Refuge include: black-billed magpie, common raven, horned lark, and rosy-finch. Spring migration usually commences mid-March. North American migrants that return to the Refuge include: American robin, dark-eyed junco, pine siskin, American goldfinch, and lark bunting. The first species to arrive from their long journey is typically either the mountain bluebird or red-winged blackbird. These two species may be coming from southern United States or all the way from Mexico!
Species that breed in North America, but winter in Mexico, Central America, South America or the Caribbean islands are called “Neotropical” migratory birds. They can travel several thousand miles to return to their breeding grounds! Other neotropical migrants that can be seen on the Refuge during the summer include: common nighthawk, belted kingfisher, western meadowlark, willow flycatcher, warbling vireo, house wren, marsh wren, yellow warbler, MacGillivray's warbler, Wilson's warbler, common yellowthroat, western kingbird, gray catbird, savannah sparrow, fox sparrow, song sparrow, Lincoln's sparrow, and white-crowned sparrow.
For more information about which species of birds can be found on Arapaho NWR please check our Wildlife List brochure and Comprehensive Conservation Plan.
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Shiras' moose were reintroduced to the North Park area in 1978 and have thrived ever since. Fifteen to twenty individuals may be found on the Refuge in spring, summer and early fall.