ID these raptors! possibly migrating? - southwestern Ontario (1 Viewer)

I was out for a walk in the woods around 7 PM last nigiht. in the Dundas Valley - South Western Ontario off the Bruce Trail near the western tip of Lake Ontario - Carolinian forest.

I saw these massive gatherings of raptors in the sky.. all circling and milling around. different groups of them spread out high above the woods. too many to count really. literally hundreds of raptors.

I took videos of the groups and also some vids of individual birds that flew closer to the ground. can anyone tell me what this was and what the raptors in the vids are? is it a migration?

I felt really lucky to witness it! I was going to go back out there today and look but it's pretty wet out. is this something that goes on for a few days? would love any info - so please have a look at the youtube links - thanks!

this first one is of them all in the sky - >

http://www.youtube.com/watch?v=mheQAxHo9Dw

and i want to know what these raptors are ->

http://www.youtube.com/watch?v=LjGdT7PJ5wE

http://www.youtube.com/watch?v=qMR64bRkZKM

http://www.youtube.com/watch?v=U_0FZfrRAhA

The group shot's are migration but very difficult to distinguish species from the footage. The single bird looks like a Turkey Vulture. Maybe get in touch with your nearest bird observatory with the date and find out what species they recorded migrating that day.

Hope it helps a bit.