Today was my day for Northern Harriers. Here is a great shot of a harrier working a field E. of Woods Road. See the white band at the base of the tail? This is the primary identifying mark for this bird. Shape-wise, they are longer and narrower than the Buteos (i.e. Red Tail Hawks).
Here's an interesting scene. Harriers often hunt in family groups (though most of the ones I see are individuals). However, they are still quite territorial. Here's a shot of a harrier chasing a vulture. Though right after I took this shot, it looked like the harrier had given up and flown to another area.