Complex patterns of moderate to heavy movements will reflect similarly complex patterns of unfavorable and favorable conditions in all the BirdCast regions for this period as the last of the spring season’s movements take place. Species on the move this week will include Spotted, Least, and White-rumped Sandpipers, Ruddy Turnstone, Dunlin, and Red Knot among a suite of other later season shorebirds, Yellow-billed Cuckoo, Alder, Willow, and Yellow-bellied Flycatchers, Gray-cheeked and Swainson’s Thrushes, Northern Waterthrush, Tennessee Warbler, Cape May Warbler, Magnolia Warbler, Bay-breasted Warbler, Blackburnian Warbler, Blackpoll Warbler, Canada Warbler, Wilson’s Warbler, and White-crowned Sparrow.
A patchwork of favorable conditions persists across the region for the weekend, with locally moderate movements occurring in the northern Rockies, Desert Southwest, and portions of the Great Basin as unfavorable winds and scattered precipitation in the Pacific Northwest and Rockies keep migrants grounded elsewhere. This pattern continues through the remainder of the forecast period, but favorable conditions expand in southern portions of the region and precipitation decreases. Light to moderate movements will be more widespread during this period, particularly from the Great Basin southward into the Desert Southwest, as the last vestiges of many species’ movements through the region pass. Species on the move this week will include Eared Grebe, Spotted Sandpiper, Pectoral Sandpiper, Western Sandpiper, Long-billed Dowitcher, Wilson’s Phalarope, Red-necked Phalarope, Common Nighthawk, Yellow-billed Cuckoo, Western Wood-Pewee, Willow Flycatcher, Pacific-slope Flycatcher, Cordilleran Flycatcher, Eastern Kingbird, Red-eyed Vireo, Veery, Swainson’s Thrush, Yellow-rumped Warbler, and Townsend’s Warbler.
Mostly favorable conditions, interspersed with scattered precipitation and some locally unfavorable winds, are on tap for the entirety of the period. Moderate movements will occur in areas free of precipitation, with locally heavy and very heavy movements likely in northern Plains region to begin and end the period. Birders should watch where precipitation and migration meet, as shore rid concentrations in appropriate habitat may occur (as well as late migrant landbird concentrations). Species on the move this week will include White-rumped Sandpiper, Black Tern, Yellow-billed Cuckoo, Common Nighthawk, Western Wood-Pewee, Least Flycatcher, Gray-cheeked Thrush, Swainson’s Thrush, Ovenbird, Northern Waterthrush, Tennessee Warbler, Orange-crowned Warbler, Nashville Warbler, American Redstart, Magnolia Warbler, Blackpoll Warbler, Wilson’s Warbler, Clay-colored Sparrow, and Rose-breasted Grosbeak.
Upper Midwest and Northeast
A patchwork of favorable and unfavorable conditions are also on tap for the region over this forecast period, with moderate to heavy movements occurring in favorable conditions, and the potential for local concentrations where birds and rain meet. Favorable conditions are sparse to begin the holiday weekend, and moderate to locally heavy movements will be similarly scattered across the region in these conditions. As the unfavorable conditions shrink to primarily Appalachian distribution by Sunday night, these movements will become increasingly more widespread. Low pressure moving through the region early in the week nearly resets the pattern, shutting down movements in many areas. However, the patchwork of favorable and unfavorable persists through the remainder of the week, despite the passage of this system. By Thursday night the Atlantic coast will experience one of the last large movements of the spring, while much of the remainder of the region is quieter in more marginal conditions. Species on the move this week will include Spotted Sandpiper, Least Sandpiper, Ruddy Turnstone, Yellow-billed Cuckoo, Acadian Flycatcher, Alder Flycatcher, Willow Flycatcher, Yellow-bellied Flycatcher, Swainson’s Thrush, Northern Waterthrush, Tennessee Warbler, Cape May Warbler, Northern Parula, Magnolia Warbler, Bay-breasted Warbler, Blackburnian Warbler, Chestnut-sided Warbler, Blackpoll Warbler, Canada Warbler, Wilson’s Warbler, and White-crowned Sparrow.
Gulf Coast and Southeast
Moderate to heavy movements west of the Mississippi River begin the weekend, while all but coastal Florida are otherwise much quitter in terms of migrants on the move. This pattern expands to the east over the weekend, as one of the last of the major spring nocturnal movements will be underway in many areas. As the work week begins, the patchwork of unfavorable and favorable conditions apparent in many other areas of the continent characterizes this region as well, with moderate to locally heavy movements occurring where favorable conditions exist and much lighter movements occurring where marginal and unfavorable conditions persist. Birders should watch the precipitation-migrant interactions carefully, as the potential for late season concentrations exists in many areas of the region over the course of the period. Species on the move this week will include Spotted Sandpiper, Stilt Sandpiper, Dunlin, Least Sandpiper, Pectoral Sandpiper, Yellow-bellied Flycatcher, Least Flycatcher, Swainson’s Thrush, Mourning Warbler, American Redstart, Yellow Warbler, Canada Warbler, Wilson’s Warbler, and Dickcissel.