April 24th, 2015

Tonight's winds. Click to view live. 

Note southerly winds in most of IL,

except in Northern IL, where rain is 

keeping birds grounded anyway.

Good news! Tonight, unexpectedly, high pressure has brought strong, southerly-based winds over Illinois. These winds are much stronger than the forecast predicted last night, and as such provide a much stronger tailwind for migrants. For these reasons, birds are moving in light to moderate concentrations tonight, save where storm systems boom overhead. But wait! There's one more detail to observe. Tonight, much of the state is glossed over by cloud cover. Because cloud cover prevents birds from reaching higher flight altitudes, they are forced to fly lower. This lower flight altitude means that if you're in an area where it isn't raining, tonight is the perfect opportunity to listen for nocturnal flight calls (NFC's). Tom Auer, a biologist with the National Audubon Society, has been sharing some fascinating content on this topic. In updates not unlike these migration reports, he focuses more on NFC's, including eBird lists detailing what calls overhead at night. Check his blog out here.

To get back to migration in Illinois, migration is essentially occurring everywhere but in Northern Illinois, where a long line of storm activity is keeping them down.

Radar at the time of this
post

In line with last night's forecast, winds are not predicted to be favorable any time soon. If tonight's forecast holds true, birds may not be moving en masse until next Saturday night. Keep in mind, however, that the further into the future a forecast is, the more subject to change it becomes. As always, I'll keep you updated.

Good stuff! Keep your eyes peeled for species whose frequencies in IL are detailed here. It's not unreasonable to expect that you'll find some new birds tomorrow, provided it's not raining where you are. Good luck to those of you who find your way out there.