White-crowned Sparrow. Bill Lee/Macaulay Library. eBird S32027821.
Locally light and moderate flights featuring Cackling Goose, Common Loon, Pacific Loon, White-winged Scoter, Ferruginous Hawk, Dunlin, Merlin, White-throated Sparrow, Golden-crowned Sparrow, and Fox Sparrow punctuated the migration scene in the West during this period, while an early and late pulse of moderate and heavy movements featuring Pied-billed Grebe, Black Vulture, Northern Harrier, Yellow-bellied Sapsucker, American Pipit, Marsh Wren, Orange-crowned Warbler, White-crowned Sparrow, Nelson’s Sparrow, Le Conte’s Sparrow, and Dark-eyed Junco graced the East.
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Moderate to locally very heavy flights were widespread in the region for the weekend as a strong frontal system passed. Moderate flights persisted into the beginning of the work week, though mostly in coastal locations where conditions remained favorable for flying. Farther west, southerly flow and scattered precipitation kept the scene much more quiet. By Wednesday night, another frontal boundary pushing through the Great Lakes and Ohio River Valley spawned moderate to heavy flights in the Upper Midwest. With the continued movement of this frontal boundary to the east, and eventually out of the region on Thursday night, moderate to locally heavy flights became more extensive.
Moderate to very heavy flights were the norm across the region to begin the period. This was particularly true in more eastern locations with the favorable winds and clear skies associated with the passage of Hurricane Matthew. Some entrainment and displacement of seabirds was associated with the passage of this storm, including inland reports of Black-capped Petrel and Sooty Tern. The days that followed saw generally decreasing extents and intensities of flights, as more southerly flow less favorable to migration set up shop in the region. But migrants took flight again on Wednesday and Thursday nights in increasingly more widespread and intense flights as a cooler air mass with northerly winds arrive.
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Great Crested Flycatcher
Black Vulture. Brian Henderson/Macaulay Library. eBird S31992765.
Scattered moderate and heavy movements occurred on several days during the period, never reaching region wide extents. The northern and eastern Plains saw action to begin the period, continuing into the early part of the work week. The most intense flights of the week occurred in the central Plains on Tuesday night, amidst scattered precipitation of a passing low pressure system, and the following night in the central and southern Plains with the passage of this system.
Locally moderate flights occurred in the region during the first half of the forecast period. These were notably in the Central Valley of California on Friday and Saturday nights, and also in the Pacific Northwest on Monday night. The second half of the period saw the greatest extent of movements on Tuesday night, with light to moderate flights scattered from the coastal mountain ranges east into the northern and southern Rockies. Light to moderate flights ended the period, particularly in more southerly reaches of the region. Note that isolated heavy movements also took place in New Mexico on Wednesday night, associated with more extensive flights to the east in favorable conditions behind a frontal passage.