Light to moderate movements in the West were most evident in the Desert Southwest and California, while strong low pressure passing through the East brought unseasonably cold and unfavorable conditions and kept most moderate movements sparse in space and time. Species on the move this week included White-faced Ibis, Chimney and Vaux’s Swifts, Olive-sided Flycatcher, many swallows, numerous warblers, Lazuli, Indigo, and Painted Buntings, Baltimore Oriole, and Yellow-headed Blackbird.
Conditions were generally much more favorable for migration farther south and west in the region over the past week. Light to moderate movements were widespread in many areas of California and portions of the Desert Southwest for the entire period. Some of these movements spilled into portions of the Pacific Northwest and northern Rockies as well, although their magnitude and extent was greatly diminished in space and time in those areas. But much of the northern and central Rockies as well as the border region experienced generally unfavorable conditions, including scattered and at times intense precipitation. Species on the move this week included White-faced Ibis, Western Sandpiper, Broad-tailed Hummingbird, Vaux’s Swift, Ash-throated and Olive-sided Flycatchers, Barn and Cliff Swallows, Varied Thrush, Sage Thrasher, Black-throated Gray, Red-faced, and Wilson’s Warblers, Black-headed Grosbeak, Lazuli Bunting, Western and Summer Tanagers, and Fox Sparrow.
Light to moderate movements that began the weekend in the Plains quickly gave way to diminishing returns as a low pressure system approached and then passed through the region. By early week migrants were basically grounded, save for widely scattered very light movements. Ameliorating conditions on Tuesday night facilitated a slight expansion of scattered light movements, but this expansion was quickly tamped by another passing disturbance. The period ended with the return of scattered light to moderate movements, particularly in the Dakotas where conditions were more favorable for migrants to move. Species on the move this week included Bufflehead, Common Goldeneye, Common and Red-breasted Mergansers, Willet, Marbled Godwit, Semipalmated Sandpiper, Wilson’s Phalarope, Franklin’s Gull, Eastern Kingbird, Scissor-tailed Flycatcher, Northern Rough-winged, Bank and Barn Swallows, House Wren, Northern Parula, Vesper Sparrow, Dark-eyed Junco, and Yellow-headed Blackbird.
Upper Midwest and Northeast
Widespread favorable conditions over the weekend spawned light to moderate flights across the region in advance of a strong low pressure system arriving from the west. By Monday cool temperatures and frozen precipitation in some areas completely shut down migration in all but the easternmost reaches of New England, where moderate migration continued. By Wednesday and Wednesday night conditions returned to a marginal state, allowing light to locally moderate movements to occur in the vicinity of southerly flow circulating around an Upper Mississippi River valley low pressure center. But primarily marginal to unfavorable conditions, particularly unseasonably cool temperatures, kept most movements to a minimum through the end of the period. Species on the move this week included American Wigeon, Northern Pintail, Green-winged Teal,Ring-necked Duck, Bufflehead, Common Goldeneye, Hooded Merganser, Horned and Red-necked Grebes, American Woodcock, Chimney Swift, Eastern Kingbird, White-eyed Vireo, Northern Rough-winged, Bank, Barn, and Cliff Swallows, House Wren, Blue-gray Gnatcatcher, Ruby-crowned and Golden-crowned Kinglets, Northern Parula, Prothonotary, Yellow-rumped and Prairie Warblers, Chipping Sparrow, and Dark-eyed Junco.
Gulf Coast and Southeast
Widespread light to moderate movements were the norm across the region for the weekend, persisting until the passage of a cold front through the region on Monday. By Monday night this system shut down movements in all but the easternmost reaches of the region (primarily Florida), where moderate and even locally heavy movements continued. With the stage reset as low pressure departed to the east, light movements occurred primarily in coastal and western portions of the region by Tuesday night. These expanded in size and extent by Wednesday, but a new round of precipitation and unfavorable conditions associated with a passing disturbance prevented their expansion much beyond Wednesday’s extent. Several accounts suggested fallouts and concentrations occurred earlier in the week along the Gulf Coast, particularly in Texas (see these reports from Galveston County, Sabine Woods and Dauphin Island), although none were massive. Species on the move this week included Wilson’s Snipe, Yellow-billed Cuckoo, Eastern Whip-poor-will, Belted Kingfisher, Yellow-bellied Sapsucker, Acadian Flycatcher, Swainson’s and Hermit Thrushes, Northern Waterthrush, Tennessee, Yellow, Chestnut-sided, Blackpoll, Black-throated Blue, and Black-throated Green Warblers, Rose-breasted and Blue Grosbeaks, Indigo and Painted Buntings, and Baltimore Oriole.