Several widespread light to moderate flights color this forecast period in the West, while a pulse of favorable conditions that produces weekend flights in the Plains and early week flights in the East eventually gives way to a strong cold front that spawns fallouts and shuts down the whole system to end the period. Species on the move this week will include Bufflehead, Great and Snowy Egrets, Swainson’s Hawk, Ash-throated and Great Crested Flycatchers, Northern Shrike, Ruby-crowned and Golden-crowned Kinglets, Blue-gray Gnatcatcher, a suite of early warblers including Nashville, Hooded, Prothonotary, Black-throated Gray, Palm and Yellow-throated, Indigo Bunting, Bullock’s, Hooded, and Orchard Orioles, and Chipping Sparrow.
Favorable conditions from the northern and central Rockies west and south through California and portions of the Desert Southwest spawn light to moderate movements to kick off the weekend, and these conditions even expand to the east by Saturday evening. But the Pacific Northwest sees precipitation shut down most movements. By Sunday evening scattered light movements will occur across the region where precipitation is not falling and away from unfavorable northerly winds. The week begins with favorable conditions returning to much of the region away from the Pacific Coast, with light to moderate movements widespread east of the Sierras and Cascades. This pattern shifts primarily to the Desert Southwest, only, by Tuesday night, and by Wednesday scattered movements are again the norm as favorable conditions are spread locally across the region. However, the end of the forecast period sees more nights with much more widespread favorable conditions, which will spawn light to moderate movements across much of the region. Species on the move this week will include Common Goldeneye, Swainson’s Hawk, Black-chinned Hummingbird, Ash-throated and Pacific-slope Flycatchers, Western Kingbird, Northern Shrike, Black-throated Gray and Nashville Warblers, Black-headed Grosbeak, Bullock’s and Hooded Orioles.
A quiet start to the weekend across all but the northern Plains, where light to locally moderate movements occur, will give way to more widespread moderate to even locally heavy movements as the weekend continues. This will be true, in particular, for the central and southern Plains. As low pressure passes the region on Monday night, only the southeastern and northwestern portions of the region experiencing favorable conditions will see light to moderate flights. As the week continues, changeable conditions bring about drastic changes in migration: moderate movements will continue in some parts of the region on Tuesday, particularly in the Dakotas and western central and southern Plains states. Wednesday night sees almost no movements, with the exception of the Dakotas and perhaps local concentrations and fallouts in the far south where migrants meet passing precipitation. Not until the end of the forecast period does another widespread moderate and locally heavy movement appear likely, as favorable conditions again are forecast to spread east over much of the region. Species on the move this week will include Snow, Ross’s, and Greater White-fronted Geese, Redhead, Ring-necked Duck, Common Goldeneye, Bufflehead, Red-throated Loon, Turkey Vulture, Bald Eagle, Swainson’s Hawk, Ring-billed Gull, Scissor-tailed Flycatcher, Tree, Northern Rough-winged, and Barn Swallows, Ruby-crowned Kinglet, Blue-gray Gnatcatcher, Northern Parula, Louisiana Waterthrush, Yellow-headed Blackbird, and Vesper, Lark, American Tree, and Chipping Sparrows.
Upper Midwest and Northeast
Away from the light to moderate (and even locally heavy) movements in the southern Ohio River valley, portions of the northern Appalachians, and some coastal locations, most of the region begins the weekend quietly. Note that some coastal areas and portions of the northern Appalachians may see precipitation-related concentrations of waterbirds and passerines depending on the timing of precipitation across the region, and birders should track this closely. By Sunday and Monday the first hints of a new pulse of migrant arrivals appears in the upper Mississippi River valley and western Great Lakes and expands into the eastern Great Lakes, Ohio River valley, and central Appalachians. The favorable conditions shift east on Tuesday night, with moderate flights occurring primarily east of the Ohio River valley. Moderate movements continue on Wednesday and Thursday farther south, as the next storm system begins to move into the region. And as this system moves east, moderate movements will be increasingly coastal until precipitation and northerly flow overspread the region and shut down migrants. Birders should watch the mid and late week distribution of precipitation as it moves east across the region, as there is potential for concentrations of waterbirds on inland bodies of water and passerines in some locations (e.g. Great Lakes, Appalachians on Thursday morning; coastal Northeast on Friday morning). Species on the move this week will include Snow Goose, Tundra Swan, Northern Pintail, Redhead, Canvasback, Common Goldeneye, Hooded Merganser, Horned Grebe, Great and Snowy Egret, Caspian Tern, Yellow-bellied Sapsucker, Eastern Phoebe, Northern Rough-winged, Tree, and Barn Swallows, Northern Shrike, Ruby-crowned Kinglet, Blue-gray Gnatcatcher, Hermit Thrush, Louisiana Waterthrush, Palm and Yellow-throated Warblers, Chipping Sparrow.
Gulf Coast and Southeast
Highly variable conditions across the region will beget highly variable extents of migrant movements to kick off the weekend. Moderate movements will occur where precipitation is not falling on Friday night and Saturday, but almost all areas see migration shut down by Saturday night after the passage of a cold front. Birders along the eastern Gulf Coast, in Florida and on the immediate Atlantic coast should watch the passage of this front closely, as its timing may spawn heavier than expected coastal flights followed by local concentrations and fallouts as precipitation falls. Moderate movements on Sunday night occur west of the Mississippi, spreading east by Monday and Tuesday nights. Note that wind conditions favor more westerly arrivals of trans-Gulf migrants, even driving some early migrants into circum-Gulf flights to begin the week. By Wednesday the threat of precipitation arrives in the region, and although many areas will experience moderate to locally heavy flights, precipitation will shut down movements in some places west of the Mississippi. Birders should monitor the arrival of this energy and precipitation closely. It is likely that fallouts will occur later Wednesday, into Thursday, and even into Friday along the Gulf coast, beginning on Wednesday primarily east of the Upper Texas Coast (but not exclusively) and spreading east on Thursday to include portions of the lower Mississippi River and Mobile river valleys. As this cold front pushes farther east to end the period, Florida and portions of the Southeastern coastal Plain may get into the action, as precipitation could spawn fallouts in the Panhandle, the Florida Keys, and in southern Georgia. Also, birders farther west of the primary zone of forecast precipitation should also keep a close eye on the wind shift that is likely to occur along the mid and lower Texas coasts by later Thursday or Friday; this wind shift will spawn fallouts and concentrations. An interesting twist to forecasts for this period is the extent of precipitation falling in parts of Central America and the Caribbean: whether migrants will take flight depends heavily on the local conditions at sunset and shortly thereafter, and if precipitation becomes more widespread than forecast, migration amounts could be significantly less than expected despite what seem to be favorable conditions in other parts of the region. Species on the move this week will include Gadwall, Ring-necked Duck, Bufflehead, Least Tern, Chimney Swift, Yellow-bellied Sapsucker, Northern Flicker, Great Crested Flycatcher, Eastern Phoebe, Eastern Kingbird, Red-eyed Vireo, Wood and Hermit Thrushes, Golden-crowned Kinglet, Brown Creeper, Worm-eating, Blue-winged, Prothonotary, Kentucky, Hooded, Yellow-rumped, and Tennessee Warblers, Indigo Bunting, Orchard Oriole, and Summer Tanager.
Farnsworth and Van Doren