Strong migration with possible PA fallout

Regional Overview

I am writing this as I listen to thrushes stream overhead, primarily Swainson’s Thrushes but there are some Gray-cheeked Thrushes mixed in as well. Last night the radar boomed with migrants as they took advantage of a return of north winds across the region. Birds were streaming over the Great Lakes (check the Buffalo radar to see them crossing early in the evening) and the flight was strong as soon as any of the storms moved through. There were storms move through so if you got precipitation last night, check your location on the radar. Areas that saw strong migration cut off by storms include southwestern and central Pennsylvania. Check for a fallout of migrants in areas where storms passed through.

The only spots that did not see a strong night of migration were areas south of the storms such as Maryland, Delaware, and southern NJ. These areas may still get a fair influx of birds as birds migrated through gaps in the weather systems but changeover should be small.


The next night with strong migration should be Friday night when north winds return. Next week will be wil bring several days of stronger west winds along the Great Lakes, hopefully bringing some jaegers and gulls to the lake watches.

I don’t always have time to comment on the radar in each state. To interpret it yourself, read the quick tutorial at the bottom of the page.

New York

Click on the thumbnail to view the full-sized animation.

Pennsylvania & New Jersey

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Southwestern and central PA show conditions favorable to a fallout with storms that moved through, interrupting a strong migration from further north. Check areas that had storms passing through last night, especially the north edge of the storms where the birds would have first run into rain.


Click on the thumbnail to view the full-sized animation.

Maryland and Delaware

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Quick guide to interpreting the radar

On the top row (reflectivity radar), the images show the magnitude of migration. When birds are migrating, it looks like a donut shape around the center of the radar station.

The bottom row is the velocity radar. This shows the direction that the objects detected by the radar station are moving. Blues are moving towards the radar station, yellows and reds are moving away from the station. So for southbound migration, blue should be on the top half of the donut, yellow on the bottom half.

Watch for precipitation moving through during the night hours, this can cause birds to stop migrating in a concentrated area, creating the fabled ‘fallout’, particularly on nights with strong migration.

For more in depth info, watch this video.
For migration updates or other regions check-

Pac NW – Birds Over Portland by Greg Haworth

I need your help! These reports will only be as good as the feedback I get on these updates. Please leave comments on interesting patterns of migration you are seeing in the field so I can incorporate some ground truthing to my forecasts and predictions. Thanks!