Mixed flock of blackbirds in late fall last year (2010), post-corn-harvest. This year's corn is still green.
I hereby record that the first megaflock* of common grackles this year arrived at my Warren County home in the pre-dusk hours of September 4th. They squeaked and creaked and occupied every ash, hickory, and sycamore branch along a half-kilometer stretch of the Musconetcong River. Then they departed, flying west-ish in the typical (and typically impressive) never-ending-river-of-birds. It would be fascinating to have a map of the wanderings of these bird-herds. Maybe ebird has this in their power?
They apparently wander this way all winter, and farther north than NJ, too. Here is a photo of another megaflock feeding on my lawn when I lived in Orange County, NY (taken December 2009).
Megaflock of grackles in Goshen, Orange County, NY, December 2009.
*I made up the word, but it fits...