National Overview

High pressure dominated the weather east of the Rockies yesterday, setting up another night of favorable winds and a relatively stable atmosphere. A band of moisture from Indiana to the Carolinas did pack a few storms last night, but as you can see from the national composite migration was evident across the entire region. If you’ve been following along the last few days, you should notice that reflectivity in the Northeastern U.S. was kicked up a notch last night as the “migration cloud” makes its way farther and farther north. Also noteworthy is the lack of migration along the immediate coast in the Mid-Atlantic; I’ll go into more detail on this in the next section. Conditions continue to favor nocturnal migration over the next 72 hours, especially for birds arriving from the Neotropics and moving north through the Central U.S. The chance of precipitation is expected to increase across the Midwest as the next front approaches early next week, but migration should still be the rule rather than the exception.

Below are the radar loops from sunset last night through 5:00am this morning

New Jersey (Mid-Atlantic)

Frames are every 1/2 hour. Click on the thumbnail to view the full-sized animation.

While the weather may be unseasonably warm, the migration patters from last night are quintessentially spring. By that, I mean, birds are concentrated along the Appalachian ‘superhighway’ and pretty obviously skirting most of southern New Jersey. Only the westernmost parts of the state appears to have been overlapped by the migration flock last night, while the bulk of birds moved up the Delaware River and crossed into the state through Central and Northern New Jersey. This trajectory favors spring hotspots in the northern half of the state but may even be too far west to produce good numbers at Garret Mountain. I imagine many of you are in the field today; lets hear your reports!

Wisconsin (Upper Midwest)

Frames are every 1/2 hour. Click on the thumbnail to view the full-sized animation.

Birds continued to push into the Upper Midwest last night with all radars indicating moderate levels of migration activity. As was the case yesterday, the general trajectory across the region was S->N with little crosswind to cause birds to drift east or west. Compared to the Northeast, though, migration densities were lower suggesting that less birds are continuing up the pipe through the Central U.S. I can only speculate on why this is, but it’s possible that short-distance migrants are sampling the habitat as they move north and finding more available food in the east relative to the Midwest. As favorable habitat opens up (insects hatch, buds on trees burst, etc.) these short-distance migrants are expected to take advantage of it. In about a six weeks, though, we would expect the long-distance migrants to saturate the system resulting in a more uniform progression across the landscape. In any case today you can expect more buildup of short distance migrant numbers at your local spring birding spot. If you get the chance, please come back and let us know where you birded and how it was. This feedback is essential for refining our understanding of migration relative to what we see on the radar. Thanks in advance!

Good Birding

David