Do Grackles Have Jobs?

Each morning, very early, we've seen Grackles heading south and then in the afternoon, around 4:30 or so, we see them coming back north...hundreds, if not thousands of them, some in groups of three or four and some in group of dozens.

So we wondered...do they have jobs? Where do they go in the morning and what do they do all day? Where do they go at night?

I Googled "Grackle daily migration" and came up with this article: Travel of Birds: Chapter III, First Flights.

So, it appears that during the day, they're going to their feeding grounds and coming back to their roosting area at night. We don't know where the roosting area is, but it would be interesting to track it down in order to see the thousands of birds roosting in one place!