Forecast and Analysis

Regional Migration Analysis: 24-31 May 2013

Andrew Farnsworth The Cornell Lab May 31, 2013

Continental Summary:

Some light to moderate movements continued in the West, as the last of the moderate and locally heavy movements occurred in the East. Species on the move this week included Ruddy Turnstone, Yellow-billed Cuckoo, Yellow-bellied and Alder Flycatchers, and Gray-cheeked Thrush. Note that our colleagues at University of Wyoming experienced some problems with the production of their synoptic and radar imagery. Because the typical presentation of weekly animated snapshots was more limited than previous weeks, the animation below shows radar mosaic imagery from the UCAR website and only for 26-31 May 2013.


With most migrants now well north in the region, it was no surprise that light to moderate movements were limited, though still present, across the region. These movements continued for the entire period, particularly close to the Pacific Coast and in portions of the Desert Southwest. Species on the move this week included Black Tern (in Washington), Olive-sided and Willow Flycatchers, Western Wood-Pewee, Gray-cheeked and Swainson’s Thrushes (in Alaska), Gray Catbird (in eastern Washington), and Yellow, Orange-crowned and Blackpoll Warblers (in Alaska).

Great Plains

Migration continued through the period, among several areas of intense precipitation and strong storms, at moderate to locally heavy levels. In particular, light to moderate movements were still apparent in scattered storms even late into the week on Wednesday and Thursday nights. This pattern was especially apparent farther north in the region, where more migrants were still passing. Species on the move this week included Yellow-billed Cuckoo, Alder and Yellow-bellied Flycatcher, Philadelphia Vireo, Sedge Wren, Wilson’s and Canada Warblers.

Upper Midwest and Northeast

Scattered light to moderate movements occurred in many parts of the region away from rain, particularly later in the forecast period. As would be expected, more northerly radars detected more intense movements, with birds continuing to move into and through those areas relative to points farther south. Highlighting this further, notice the relative dearth of targets farther south despite favorable conditions to move on some nights (particularly Wednesday and Thursday nights). Species on the move this week included Black-billed and Yellow-billed Cuckoos, Alder and Yellow-bellied Flycatchers, Gray-cheeked Thrush, Cedar Waxwing, and Mourning Warbler.

Gulf Coast and Southeast

With the exception of Texas, where light to locally moderate movements occurred during the forecast period, most of the region saw little additional movement on radar. Numbers of birds actively migrating in the Southeast have dwindled, other than perhaps shorebird movements along primarily coastal areas. Species on the move this week included Ruddy Turnstone, Red Knot, Black Tern, and a scattering of late passerines including Yellow-bellied Flycatcher and Gray-cheeked Thrush.

This post marks the end of regular Spring 2013 regional migration forecast and analysis reports. Regular updates to the site will continue through the summer, and weekly forecast and analysis will begin again on 1 August 2013.