Light to moderate movements are the norm across the country this week as species diversity and numbers pass peak in many areas, although some locally heavy movements begin the period in the Southeast. Birds on the move this week include Bufflehead, Hooded and Red-breasted Mergansers, Ruddy Duck, Common Loon, Horned Grebe, Bonaparte’s Gull, Hermit Thrush, American Robin, American Tree Sparrow, and Dark-eyed Junco.
Favorable conditions for movement exist in many areas of the region to begin the weekend, but densities of birds will be low given the late date. Scattered light movements will occur in many areas West of the Rockies, with heavier movements possible close to the Pacific Coast. This pattern comes to an end on Monday, as low pressure moving through the Great Basin and northern Rockies begets mostly unfavorable conditions. However, portions of the Pacific Northwest will experience light to moderate movements if this system moves sufficient far to the East. As the week continues, light to locally moderate movements will become increasingly widespread, particularly to end the period, as more favorable conditions prevail in many areas. Some areas may see late season concentrations or small-scale fallouts where birds and precipitation meet, particularly waterfowl on inland bodies of water. Birds on the move this week include Bufflehead, Common Goldeneye, Red-breasted and Hooded Mergansers, Turkey Vulture, Red-tailed Hawk, Bonaparte’s Gull, Hermit Thrush, and Dark-eyed Junco.
The northern and central Plains see moderate movements over the course of the weekend as high pressure moves across and also to the North of the region. However, as the high builds over the Canadian Prairies on Monday, strongly easterly flow spreads over the region and shuts down most movements. As this high drifts Southeast, conditions remain largely unfavorable for movements. However, late week will see the passage of a low pressure system that will spawn moderate movements in the northern Plains to end the period. Birds on the move this week include Snow, Ross’s, and Cackling Goose, Canvasback, Ruddy Duck, Common Loon, Bald Eagle, Bonaparte’s Gull, American Tree, Fox, and Harris’s Sparrows, Dark-eyed Junco, and Purple Finch.
Upper Midwest and Northeast
Moderate and some locally heavy movements kick off the weekend to the East of the Appalachians, as much less favorable conditions farther West shut down most movements. A quickly passing low moves across the northern reaches of the region over the weekend, bringing light to moderate movements first in the Great Lakes and then to New York and New England by Sunday night. High pressure behind this system builds over the Canadian Prairies on Monday night, and brings northeasterly flow to many areas East of the Mississippi; widespread light to moderate movements will ensue. By Tuesday and Wednesday, however, these movements become increasingly localized to the Atlantic Coast and eventually the mid-Atlantic Coast as the high moves East. Birds on the move this week include Brant, Bufflehead, Common Goldeneye, Black and White-winged Scoter, Red-breasted and Hooded Mergansers, Common Loon, Horned Grebe, Turkey Vulture, Eastern Phoebe, American Robin, Yellow-rumped Warbler, Snow Bunting, American Tree, Chipping, White-throated and White-crowned Sparrows, and Dark-eyed Junco.
Gulf Coast and Southeast
One of the last or the last of the moderate to heavy movements occur in and East of the Appalachians to kick off the weekend, as high pressure moves into the region. Once high pressure moves through the region, conditions become marginal at best and movements will be mostly light to moderate, scattered widely across the region. As the week continues, high pressure moving to the North of the region brings favorable conditions to portions of the region in and East of the Appalachians, again, where light to moderate movements will occur through midweek. However, by week’s end unfavorable conditions prevail in most areas as a strong high moves off the mid-Atlantic Coast. Birds on the move this week include Ring-necked Duck, Lesser Scaup, Hooded Merganser, Common Loon, Hermit Thrush, American Robin, Yellow-rumped Warbler, Chipping, Field, Savannah, Song, White-throated and White-crowned Sparrows, and Dark-eyed Junco.
A Cave Swallow Aside
As low pressure moves from the Desert Southwest across the Great Plains and into the Great Lakes to end this forecast period, birders in the Upper Midwest should be watching for a push of Cave Swallows. We will update this story during the course of the week as conditions change, or warrant, despite the fact that this system is still a week away.