Forecast and Analysis

Regional Migration Analysis: 8-15 August 2014

Andrew Farnsworth The Cornell Lab Aug 15, 2014

Continental Summary

Locally light to moderate movements in the West over the weekend and a pulse of more widespread light to moderate movements from the Great Plains through the Southeast to begin the work week were the primary migration highlights on radar for the week. Species on the move this week included Northern Shoveler, Green-winged Teal, Blue-winged Teal, Black-bellied Plover, Lesser Yellowlegs, Upland Sandpiper, Least Sandpiper, Stilt Sandpiper, Black Tern, Olive-sided Flycatcher, Red-eyed Vireo, Wilson’s Warbler, Yellow Warbler, Black-and-white Warbler, and Rose-breasted Grosbeak.


Light to moderate migration was scattered locally across the region during the week, as several disturbances produced scattered precipitation that moved through many portions of the West. The most substantial movements were over the Central Valley area of California and over the eastern fringes of the region from Montana south along the eastern Rockies, but even these were not intense or extensive. Species on the move this week included Northern Shoveler, Wilson’s Warbler, Yellow Warbler, Northern Pintail, MacGillivray’s Warbler, Green-winged Teal, Wood Duck, Barn Swallow, and Gadwall.

Great Plains

Some serious weather that bisected the region over the weekend gave way to widespread light to moderate movements by Sunday night in more favorable, northerly flow. These movements diminished quickly, however, as return flow and an approaching area of precipitation brought marginal then increasingly unfavorable conditions that kept migration light to locally moderate for the remainder of the period. Species on the move this week included Red-eyed Vireo, Least Flycatcher, Eastern Wood-Pewee, Black-and-white Warbler, Gray Catbird, American Redstart, Rose-breasted Grosbeak, and Prothonotary Warbler.

Upper Midwest and Northeast

Scattered light movements for most of the region kicked off the weekend, with the exception being portions of the western Great Lakes and Mississippi River valley that experience more moderate movements. This pattern continued through midweek until the passage of a frontal boundary shuffled the deck, allowing more widespread light to moderate movements across the region by Wednesday night. These movements continued on Thursday night, albeit more scattered, less intense but generally increasing from north to south. Species on the move this week included Pectoral Sandpiper, Lesser Yellowlegs, Olive-sided Flycatcher, Stilt Sandpiper, Turkey Vulture, Blue-winged Teal, Red Knot, Least Sandpiper, Northern Shoveler, Tree Swallow, Black Tern, and Black-bellied Plover.

Gulf Coast and Southeast

Light to moderate movements were the norm this week, as birds likely began to outcompete bats and insects in radar scans across the region. Sunday to Tuesday nights showed the most extensive movements, including some isolated and local heavy movements mostly west of the Mississippi. The extent of movements gradually shifted east and south over the course of the forecast period, with more moderate movements becoming primarily coastal by week’s end. Species on the move this week included Yellow Warbler, Black-bellied Plover, Little Blue Heron, Osprey, Piping Plover, Upland Sandpiper, Snowy Egret, Blue-gray Gnatcatcher, Willet, and Ring-billed Gull.