Acadian Flycatcher. Tyler Flicker/Macaulay Library. eBird S36894510.

Continental Summary

BirdCast regional analyses return after our global big day absence! Widespread light and moderate to locally heavy flights characterized the first days of this long forecast period in the West and featured Willow Flycatcher, Dusky Flycatcher, Western Wood-Pewee, Swainson’s Thrush, MacGillivray’s Warbler, Yellow Warbler, and Black-headed Grosbeak, while  moderate to very heavy flights occurred in the latter two thirds of the two-week period in the East, first in the Plains and then farther to the coasts, featuring Alder Flycatcher, Yellow-bellied Flycatcher, Philadelphia Vireo, Bay-breasted Warbler, Magnolia Warbler, Canada Warbler, and Wilson’s Warbler.

Curious what birds will move next? Check out our forecast.

Need a review of our definitions for regions, species on the move, and migration amounts? Please visit this link.

Quick Links to Regions

Upper Midwest and Northeast	Gulf Coast and Southeast
Great Plains	West

Upper Midwest and Northeast

A strong frontal passage in the first days of the period kept most migrants on the ground away from the Upper Midwest, where locally moderate to heavy flights persisted. These flights intensified in the days that followed, building into the Ohio River valley by 8-9 May. These flights never became widespread across the region, as another frontal passage kept birds on the ground in precipitation as it passed 10-12 May. However, some locally intense flights continued around the region during this passage, in particular in coastal and Great Lakes locations. The passage of this strong low pressure system through the Northeast kept a set of primarily unfavorable and marginal migration condition in place there, while the remainder of the region experienced moderate to heavy flights through 15-16 May. It was not until 16-17 May that more extensive intense movements reached areas of the coast and New England. By the end of the period, locally moderate and isolated heavy flights were scattered across the region as more marginal conditions with precipitation filled into many areas of the region.

Top Movers

Increasing

Decreasing

Yellow-bellied Flycatcher. Sandy Aubol/Macaulay Library. eBird S36948706.

Gulf Coast and Southeast

Moderate to heavy flights dominated the migration scene for the first 5-6 nights of the period, in particular to the west of the Mississippi River. A frontal passage around 12-13 May quieted these flights, and generally slowed movements across the region. This frontal passage was intense and extensive, muting trans-Gulf flights for the days that followed in the central Gulf of Mexico region in particular. This was perhaps most noticeable in the distribution of nocturnal flights from 14-19 May, for example the lower magnitude flights in portions of the central and eastern Gulf states. By the end of the period, most of the action, which was represented by moderate intensity flights, was in Texas and Peninsular Florida.

Top Movers

Increasing

Decreasing

Philadelphia Vireo. David McQuade/Macaulay Library. eBird S36833439.

Great Plains

A series of moderate to heavy flights from 5-8 May kicked off this period, with the most intense and extensive movements on 6-7 May. More local moderate to heavy flights continued thereafter, mostly in the northern and central Plains, particularly on 12-13 May. Similarly intense and local flights continued through much of the remainder of the period. But 17-19 May saw a noticeable decline in intensities and extents as strong storms passed through the region, shutting down movements where they passed.

Top Movers

Increasing

Decreasing

Swainson’s Thrush. Tony Varela/Macaulay Library. eBird S36893060.

West

Moderate to locally heavy flights occurred from 5-7 May, particularly from California and the Desert Southwest east and north along the Rockies. These flights shut down as widespread precipitation created much less favorable conditions, with largely light to locally moderate flights in the days that followed. California and Montana were exceptions, as more intense flights continued in those locations. By 11-12 May light to moderate flights were apparent, primarily in the Desert Southwest. But following these movements conditions were generally much less favorable for flights, with precipitation and unfavorable winds keeping migrants grounded in many areas. Light to locally moderate flights persisted in some locations through the period, especially in California and in portions of the Desert Southwest and northern and southern Rockies.

Top Movers

Increasing

Decreasing

–––––––––––––––––––––––––––––––––––

Farnsworth and Van Doren