Scattered light to moderate movements expand across the region by early week in the West, fallouts spread east from the Texas coast from the weekend through early week as a cold front stalls in the Gulf of Mexico, and the East sees a big pulse of migrants to end the forecast period. Species on the move this week will include Swainson’s Hawk, Franklin’s Gull, Chimney and Vaux’s Swifts, Blue, Rose-breasted, and Black-headed Grosbeaks, Lazuli and Indigo Buntings.
Scattered light to moderate movements will be the norm to begin the weekend. Birders in the Pacific Northwest, central and northern Rockies, and Great Basin should watch precipitation closely, as local fallouts are possible where the forecast scattered precipitation will fall. Some areas of the eastern Rockies will experience heavier movements in highly favorable conditions. As the weekend continues, movements decrease in size and extent and become increasingly restricted to the northwestern parts of the region. However, Monday sees the beginning of a pattern of increasingly favorable conditions take hold, and movements will become increasingly more widespread and reach moderate levels in a number of areas from the Central Valley to the northern Rockies and in the eastern Rockies. As this pattern builds, movements will become less apparent in parts of the Pacific Northwest and Great Basin, instead dominating in the Desert Southwest and Four Corners. Species on the move this week will include American Wigeon, White-faced Ibis, Swainson’s Hawk, Franklin’s Gull, Vaux’s Swift, Black-chinned Hummingbird, Ash-throated Flycatcher, Bank, Cliff, and Barn Swallows, Ruby-crowned Kinglet, Townsend’s, Nashville, Black-throated Gray, and Wilson’s Warbler, Yellow-headed Blackbird, Lazuli Bunting, Black-headed Grosbeak, and Fox Sparrow.
Moderate to locally heavy movements may kick off the weekend in the western portions of the region, while lighter movements certainly will prevail farther east. This duality is largely a function of changing conditions bisecting the region, with northerly flow departing to the east and southerly flow arriving from the Rockies. The extent to which these conditions move into the region will define the extent of heavier movements. The favorable conditions expand in many areas by Saturday night, but passing low pressure and associated storms increasingly shut down most migrants by Sunday night. This shut down prevails through Tuesday, when the atmosphere begins to change and a similar pattern to that of the previous days returns. By Wednesday night moderate to heavy movements will occur across the region as favorable conditions overspread the entire Great Plains. Some areas of the central and southern Plains may even experience very heavy movements. These movements continue in the central and southern Plains on Thursday night. Species on the move this week will include Red-breasted and Common Mergansers, Great and Snowy Egrets, Osprey, Swainson’s Hawk, Marbled Godwit, Franklin’s Gull, Chimney Swift, Scissor-tailed Flycatcher, Barn Swallow, Brown Creeper, Blue-gray Gnatcatcher, Northern Parula, Yellow-headed Blackbird, Lark, Chipping and Fox Sparrows, and Dark-eyed Junco.
Upper Midwest and Northeast
Low pressure and cold and wet conditions move through the region to kick off the weekend, but portions of northern New England and the Great Lakes and Ohio River valley still experience scattered light to moderate migration in pockets of favorable conditions. As the system barrels through, most of the region then shuts down for Saturday night. But a new swath of favorable conditions begins to cut into the western Great Lakes, the Upper Mississippi River valley, and portions of the mid Atlantic and New England states, bringing moderate movements in those areas. As a new low pressure system intensifies in the Mississippi River valley, favorable and marginal conditions are scattered across the region and will spawn light to moderate movements where such conditions occur. By Monday night this system spins northeast and creates a similar pattern to the previous weekend, with movements isolated in pockets of favorable conditions on either side of the system’s frontal boundaries. The departure of this mess sees northerly flow return to most of the region away from New England and shuts down most movements. But Wednesday night has return flow in the forecast for the western Great Lakes and Upper Mississippi River valley, spawning a return of moderate and even locally heavy movements in those areas; however, the Appalachians and Atlantic coast remain under the influences of unfavorable northerly flow. To end the week, this return flow overspreads most of the region and moderate to heavy movements will be widespread. Species on the move this week will include American Wigeon, Northern Pintail, Canvasback, Hooded Merganser, Green Heron, Broad-winged Hawk, Ring-billed Gull, Caspian Tern, Yellow-bellied Sapsucker, Northern Rough-winged and Barn Swallows, Hermit Thrush, Brown Thrasher, Blue-gray Gnatcatcher, Ruby-crowned Kinglet, Northern Parula, Yellow-throated, Yellow-rumped and Palm Warblers, and Chipping Sparrow.
Gulf Coast and Southeast
A cold front is sweeping across the region, and fallouts will be occurring to kick off the weekend in numerous coastal areas along the western and central Gulf Coast. Moderate movements will continue ahead of the front in Florida and along the Atlantic coast. Fallouts continue along the Gulf Coast on Saturday as trans-Gulf migrants from points south meet the stalled frontal boundary over the Gulf of Mexico. Movements over land across the remainder of the region are largely shut down in the wake of the frontal passage. Note that some portions of southern Florida and central and western Texas may see light to moderate movements in pockets of more favorable conditions. The fallout situation continues on Sunday, and as the frontal boundary begins to organize more migrants from the south will encounter precipitation and northerly flow. Most overland movements are still shut down by unfavorable conditions on Sunday night, but the potential for overland movements that are moderate and even locally heavy exists in Florida. Fallout potential will be focused between the Mississippi River and Florida Panhandle by Monday. Pushing farther east by Monday night, only localized movements will be evident, although Tuesday will bring the fallout show to southern Florida. Not until Tuesday night does this low pressure system depart, and by this point unfavorable conditions will spread across the region. However, light to moderate movements are possible in areas with lighter winds, despite northerly flow, given that some birds will have been grounded for several days. Wednesday night sees the first return of moderate movements, with some locally heavy, to Texas and Louisiana, as favorable conditions return. However, input of new trans-Gulf migrants is unlikely given the generally unfavorable conditions continuing over the Gulf of Mexico and in northern Central America. Thursday night will again see widespread moderate to heavy movements overland, but little if any trans-Gulf migration input. Species on the move this week will include Green-winged and Blue-winged Teal, Bufflehead, Least Tern, Yellow-bellied Sapsucker, Northern Flicker, Western and Eastern Kingbirds, Red-eyed Vireo, Wood Thrush, American Redstart, Tennessee and Kentucky Warblers, Orchard and Baltimore Orioles, Scarlet and Summer Tanager, Rose-breasted and Blue Grosbeaks, and Indigo Bunting.