Forecast and Analysis

Regional Migration Analysis: 9-16 August 2013

Andrew Farnsworth The Cornell Lab Aug 16, 2013

Continental Summary

Light to moderate movements were the norm for the West and the East this week, as fall migration gradually becomes more apparent with each week. Birds on the move this week included Great Egret, Baird’s, White-rumped, Solitary, and Pectoral Sandpipers, Barn Swallow, Purple Martin, Yellow and Wilson’s Warblers.


Light to locally moderate movements were apparent for much of the week where rain was not falling, particularly in the Central Valley of California and in portions of the Desert Southwest. Birds on the move this week included Solitary and Baird’s Sandpipers, Gray and Willow Flycatchers, Hermit, Townsend’s, Yellow, Wilson’s and MacGillivray’s Warblers, Black-headed Grosbeak, and Lazuli Bunting.

Great Plains

Light and locally moderate movements in the southern Plains highlighted an otherwise quiet end to the weekend. Light to moderate migration continued and expanded slightly across the region to begin the week, particularly in the southern Plains. This pattern became more muted through the end of the period, with widely scattered light movements diminishing after the middle of the week as precipitation spread locally across the region kept many birds grounded. Birds on the move this week included Great Egret, Green Heron, Mississippi Kite, Stilt Sandpiper, Ruby-throated Hummingbird, Alder Flycatcher, Purple Martin, Barn Swallow, Yellow Warbler, and Orchard Oriole.

Upper Midwest and Northeast

Light to moderate migration peppered the region, with the largest movements from the Mississippi River valley East through the DelMarVa and New Jersey coastline to start the forecast period. The beginning of the work week saw most movements East of the Mississippi shut down by unfavorable conditions, including persistent and sometimes heavy rain, with the exception of portions of the Upper Midwest and western Great Lakes. Beginning midweek and continuing through the end of the period, light migration was apparent in a number of locations with some localized moderate movements, particularly from the western Great Lakes South and East through the central Appalachians.┬áBirds on the move this week included Great Blue Heron, Great Egret, Black-bellied Plover, Lesser Yellowlegs, Least, White-rumped, Pectoral, and Solitary Sandpipers, Bonaparte’s Gull, Black, Forster’s and Common Terns, Chimney Swift, Bobolink, and Baltimore Oriole.

Gulf Coast and Southeast

The weekend began with a substantial movement over parts of Texas, generally diminishing rapidly farther East toward the Atlantic and Gulf Coasts. Primarily light and scattered moderate movements were the norm for the rest weekend and to begin the week, as unsettled weather kept many birds where they were. Many birds chose to migrate when they could, so early nocturnal movements were apparent in advance of later evening shut downs in many locations. Light to moderate movements rounded out the period, occurring when and where precipitation was not falling (e.g. terminus of the Appalachians West through the Sabine River). Birds on the move this week included Anhinga, Great Egret, Green Heron, Greater Yellowlegs, Upland Sandpiper, Wilson’s Phalarope, Black Tern, Barn Swallow, and Yellow Warbler.