Migrants just making it into New Jersey

Here’s the radar from sunset last night through 5:00am this morning.

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

Base Reflectivity image from Fort Dix Base Velocity image from Fort Dix Base Reflectivity image from Dover AFB Base Velocity image from Dover AFB Base Reflectivity image from Upton NY Base Velocity image from Upton NY Composite Base Reflectivity image from the Northeastern USA 

To explain what you see on the radar last night, you have to consider the strong Low pressure system churning south of the Great Lakes and the associated warm front strewn across southern New Jersey. Together these two features created a barrier to any major push of birds to the north. This barrier, though, was porous, at least at its eastern extent, which can be seen in the Fort Dix and Upton, NY radar loops. It’s quite fascinating to watch, actually, so let’s dig in:

Southerly flow over most of the country resulted in another night of heavy migration with the heaviest flights occurring in the wedge of high pressure bounded in the west by a strong frontal boundary extending diagonally from north Texas to the Great Lakes (including the low pressure systems I mentioned previously). Within this zone of migration, the heaviest flights were over the southern states, as we continue to see the birds from previous Trans-Gulf and Caribbean flights move their way up through the US.  Migration over Pennsylvania was particularly high but stopped short along the southern New York border where the frontal boundary lay. Migration over the Mid-Atlantic was heaviest over the Delmarva, but tapered off quickly over southern New Jersey due to the presence of the same warm front stretched W-E across the state. Over New Jersey, the bulk of arriving migrants appear to have pushed up over the western Delaware Bay which should favor locations such as National Park dredge spoils, Palmyra, and other sites along the Delaware River. A smaller push of birds could be seen punching through the front along the east coast, a few of which appear to have stopped at Sandy Hook while most of them can then be seen entering the NY radar. Little to no movement could be detected on the radar for Central and Northern New Jersey suggesting that a) any birds that were present yesterday are still today, or b) birds were making local movements under the radar’s view. I would think that the truth is somewhere in between as we know that birds do make local movements into better stopover habitat when held over for multiple days.

Depending on how much south remains in the winds tonight, we could see a more coast-favorable flight this evening and into tomorrow. So stay tuned as I’ll be posting to Twitter if things shape up tonight, and as always will have the radar up right here in the morning.

Good Birding


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