Moderate movements, particularly in the latter half of the period from California and the Desert Southwest, included Spotted Sandpiper, Wilson’s Phalarope, Olive-sided Flycatcher, Western Wood-Pewee, Swainson’s Thrush, Yellow-breasted Chat, Western Tanager, and Black-headed Grosbeak in the West, while the migration machine kicked into a higher gear with moderate to heavy flights in the East that included Least Flycatcher, Philadelphia Vireo, Veery, Mourning Warbler, Bay-breasted Warbler, Black-throated Green Warbler, Yellow-breasted Chat, Rose-breasted Grosbeak, Dickcissel, Orchard Oriole, and Baltimore Oriole.
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A wave of cooler temperatures in the region kept a lid on migration for much of the period. Light to moderate movements were scattered locally across Great Lakes and Mississippi and Ohio River valleys early, with even more widely scattered light movements in New England during this window of time. By Tuesday and Wednesday, more moderate flights were apparent in the mid Atlantic states and into New England, but these events never expanded far beyond these areas. Although New York, New Jersey, and portions of New England saw some of these moderate flights to end the period, another weak disturbance passing through the Appalachians had already shut down or inhibited most movements elsewhere. A bit farther afield, some interesting European migrants appeared close to or just into the North American realm, including a Eurasian Hobby, European Golden-Plovers, and Black-tailed Godwit.
Widespread moderate to heavy migration took place, particularly on Saturday night along the entire Gulf Coast, as many concentrated and grounded birds and arriving trans-Gulf migrants took flight. This intensity and extent of migration did not continue unabated far into the work week, with a strong low pressure center ushering a wave of unfavorable conditions on Tuesday and Wednesday for all areas away from Florida and the southeastern coastal plain. With its departure and high pressure prevailing and moving east, moderate movements returned to much of the region on Wednesday night and increased in intensity for most of the region on Thursday night.
A patchwork of light to moderate movements peppered the region for the first half of the forecast period, with weak disturbances and associated precipitation grounding birds in some areas. However, with the departure of these conditions to the east, Tuesday night saw the beginnings of more regional light to moderate flights. By Wednesday night migration had increased to more moderate levels in more areas, particularly in the southern Plains. And despite an approaching frontal boundary moving across the northern Plains, moderate to locally heavy movements bloomed in the central and southern Plains.
Scattered precipitation kept migrants on the ground in a number of the recently hotter zones of migration for the weekend and early work week. But Monday night brought more favorable conditions, particularly from California into the Desert Southwest, where moderate movements occurred. These movements were more widespread on Tuesday night, not only in evidence in these areas but also along the eastern front of the Rockies. The end of the period mostly saw the extent and intensity of these flights continue from California east through the Rockies. Note that the Pacific Northwest did not experience much of a flight week, experiencing instead generality less favorable conditions for birds to move.