Buzzard habits

Not sure where to post this, but figure general conversation amongst farmers would seem natural. Several years ago there was a huge black buzzard roost in some trees at the cities cemetery. Always thought that was a tacky embarrassing thing to tolerate, but it seems to have dwindled to just a few. Back when there were large numbers I would often see them flying out of a morning in a fairly straight way heading in the same direction sometimes count 50 or more coming from that direction probably five or six miles from that roost. Had t noticed that kind of behavior or numbers for several years, had just seen 2-5 circling around like they were looking for something like buzzards do on about any given day. Then over the last few weeks of a morning I have noticed as many as in the twenties flying straight over In a similar pattern from a different direction. My conclusion is there must be another size able roost in the area. Makes me nervous cause we haven’t had any issues for a few years, but with those numbers flying in lose proximity to each other they could really cause trouble for cows calving. I wonder if they eventually disperse and go different ways or if they have a destination area that go to. What ever they do I don’t want them stopping off around here we are now and will through March/April be having cows calving?