The folks at eBird are helping with research into the steep declines of Rusty Blackbirds, and they need your help. According to the website....
Please help provide information on Rusty Blackbird migration by searching for Rusties this March and April in any potentially suitable habitat [like the Celery Farm!] and reporting those sightings to eBird.
You can scout anywhere throughout the Rusty Blackbird’s range- across the eastern United States, throughout the Midwest, and into Canada (http://www.allaboutbirds.org/guide/Rusty_Blackbird/id).
This wetland-loving species can be found in some surprising places, so don’t be surprised if you catch a sighting or two in a place you wouldn’t consider a birding hot spot.
Rusties can be found in many habitats from beautiful bottomland hardwood swamps to waterfowl management areas to flooded ditches by the side of the road, so feel free to get creative in your search for this bird!
More info here.