For the fourth consecutive night, birds head south over the region. Here’s the radar from 7:30pm last night through 5:00am this morning.

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

Looking at the regional composite, we see a light and tight migration event across the east coast, a product of four straight nights of bird-friendly weather. The individual base reflectivity loops show the characteristic ‘blooming’ signature of nocturnal bird migration. Upper-level winds at 8pm last night were from the ENE at 15-25kts across the region, while movement across the radar ranged from 20-40+ kts on a NE->SW trajectory, suggesting that birds were correcting somewhat for the sidewind they were experiencing (and also provides more support for these targets being birds rather than insects or other aerial plankton which cannot correct for drift).

This major axis of migration will favor hotspots along the interior ridges of NJ, along the Delaware Bay shore, and the Delaware River this morning. Coastal locations such as Sandy Hook should have new birds early (as moderate densities are passing over The Hook from Long Island this morning) but most should move inland as the morning progresses given the wind direction. Cape May will see another good day today as geography stacks the cards in her favor once again.

In the short term, expect winds to turn more southerly as the next cold front approaches from the west today and likely shuts down migration for tonight. Tuesday night is looking like the next favorable night for migration, although conditions are expected to deteriorate in short order into Wednesday morning. On Wednesday night expect a large system to track west across Central Canada bringing more southerly flow into the latter half of the week… when this clears, though, we should see some NW winds triggering migration over the region. Stay tuned to find out when that will be!

Good Birding

David