Forecast and Analysis

Regional Migration Analysis: 30 March – 5 April 2013

Andrew Farnsworth The Cornell Lab Apr 05, 2013

Continental Summary:

Numerous species were on the move in the West this week where light and moderate movements occurred in many areas, whereas hints of the opening of the flood gates to come appeared in several fallouts and some locally moderate and even heavy movements in the East. Please click here for an animation of events for the week of 30 March – 5 April 2013 described below.


As forecast, light to moderate migration prevailed in many areas of the region this week. Although some scattered precipitation kept birds on the ground in some places, generally light winds associated with high pressure over the Sierras and central Rockies facilitated these movements. This was particularly true for areas of the Pacific Coast and Desert Southwest, especially on 3-4 April. Species on the move this past week included Black-chinned Hummingbird, Ash-throated Flycatcher, more Western Kingbirds, Black-throated Gray Warbler, and Black-headed Grosbeak.

Great Plains

The moderate movements that began the period quickly gave way to a migration shutdown as a strong high pressure center built over the region. By midweek local light movements were again occurring. However, another high pressure center moving East kept migration in check, mostly, for the remainder of the period. Species on the move included Eared Grebe, Turkey Vulture and Osprey, more swallows, Brown Thrasher, and Vesper Sparrow.

Upper Midwest and Northeast

30-31 March was the first substantial movement on radar for the spring, with primarily light but locally moderate movements occurring as warm fronts flanked the region to the south and west. Of interest was a large movement of migrants reported from New Brunswick by Stuart Tingley. These early movements were short-lived, as high pressure dominated the region through midweek. However, as the high moved east, light and locally moderate movements occurred in the Upper Mississippi River valley and western Great Lakes. Scattered light and local moderate movements occurred to end the week from the Ohio River valley north and east through New York and New England as rain pummeled the Mid-Atlantic states. Species on the move included Great Egret, Laughing Gull, continued influxes of swallows, Eastern Phoebe, Golden-crowned Kinglet, and more Blue-headed Vireos and Palm Warblers.

Gulf Coast and Southeast

The weekend saw rather widespread light and moderate movements across the region as a frontal boundary advanced toward the Gulf Coast. By Monday night the system was more organized in the East, slowing movement there, whereas light movements continued throughout much of Texas. However, the arrival of the front in the western Gulf of Mexico on Tuesday created fallouts and subsequently shut down most flights. For a taste of these fallouts, which occurred along the Texas and Louisiana coast, click on the orange balloons on the maps for Worm-eating WarblerBlack-and-white Warbler, Yellow-rumped Warbler, and Swainson’s Warbler from Texas and Prothonotary Warbler from Louisiana. As these events transpired in the western portion of the region, some moderate to heavy movements were occurring in Alabama, Florida, and Georgia. As the front pushed farther south and east, only the southern portion of the Florida peninsula saw movements continue, whereas many coastal hotspots in the western Gulf saw quite a show of grounded migrants. By Thursday night all but the southernmost reaches of Texas and the immediate vicinity of the Atlantic coast from the Florida keys north to the Georgia and Carolina borders experienced a return of light and moderate movements. Species on the move included more Chimney Swifts, Great Crested Flycatcher, Red-eyed Vireo, numerous warblers (Tennessee, Worm-eating, Blue-winged), Summer Tanager, Indigo Bunting, and Orchard Oriole.