The Avian Spring Migration

Across central latitudes of North America, the avian spring migration extends from February through May.  During this time, summer residents are arriving from the south, winter residents are leaving for their northern (or mountain) breeding grounds and other migrants are merely passing through, on their way from wintering areas (to our south) to breeding areas (to our north).

Migrant snow geese, northern white-fronted geese and American white pelicans are among the early migrants, often heading north by February.  During March, the duck/loon/grebe migrations begin to heat up and hardy summer residents appear; the latter include American woodcocks, eastern phoebes, mountain bluebirds and tree swallows.  Early shorebirds may also turn up in March though the number and variety of shorebirds usually peaks in mid-late April.  Mid April is an interesting time for birders since the wave of summer residents begins to increase and the last of the winter residents begin to depart; among the former are house wrens, hummingbirds, chipping sparrows, a host of swallows, chimney swifts, rails, migrant gulls and terns, gray catbirds and yellow-rumped warblers while the latter include white-crowned and white-throated sparrows and dark-eyed juncos.  Late April through early May brings the peak wave of migrant warblers, flycatchers, common nighthawks, rose-breasted grosbeaks, tanagers and migrant thrushes, among others.  By mid May, the migration show is over but fall migrants (i.e. early shorebirds) will be turning up in July.

Here on our Littleton, Colorado, farm, the migration schedule is unfolding right on schedule.  The dark-eyed juncos have all but disappeared and both house wrens and broad-tailed hummingbirds have appeared this week.  Our lone Townsend's solitaire has yet to depart but his days on the farm are numbered.  The next few weeks will be especially interesting.