The winds over Florida were ENE last night, so the lack of major migration in the southern half of the state likely reflects an exhausted pool of migration-ready birds. Here’s the radar from 7:00pm last night through 5:00am this morning.
Actually, the reality of last night’s migration appears far more complicated than I made it sound above. Okay, let me try and sort this out…
If you look at the composite image, you can see strong signals across North Florida, the Panhandle, and the southeastern US, suggesting a very heavy influx of birds into the state. Look specifically at the Jacksonville radar, as well as the radars over Charleston, SC and Georgia. Between midnight at 4am these radars go almost totally green… and each of them shows strong NE->SW flow at speeds consistent with migrating birds… if these are all birds, it represents the densest concentration of migrants I can remember ever seeing on the radar from any one location.
As you move down the state, though, migration activity decreases precipitously. Birds are on the move across the entire state, but only at low to moderate densities despite optimal conditions. This is quite common after a few good nights of migration, where the pool of available migration-ready birds has been depleted. Hopefully the folks out at Cape Florida can give us an idea of their recapture rate today, which would indicate what proportion of birds are sticking around vs. being replaced by new ones (although a few banding stations worth of data would be helpful in this regard). Birding conditions in the upper Keys should be good today, as the birds which did move over Miami last night appeared to be heading due south with little sign of movement beyond the island chain. Otherwise conditions in the central and southern part of the state should remain similar to yesterday. North Florida and Panhandle birders should be on the lookout for high densities of new birds dispersed across tried-and-true fall migrant traps, with the east winds favoring slightly inland or west coast locations.