Huge kettle of Swainson's Hawks coming to roost - October 2014

While driving home around 5:30 p.m. my wife and I were stunned to see Swainson's Hawks gathering from every direction and forming this large kettle of 200+ birds. They swirled around and came quite close to this very large row of trees where approximately 30 Turkey Vultures were already roosting. They never would quite land, but instead would gain altitude and then come back down and so on and so on. The kettle grew and grew just a couple hundred feet from the ground. Some of the birds were a mere 40 feet high! After observing this remarkable behavior for about 30 minutes suddenly, as if on cue, they all rose in unison and started to peel off in small groups as they hastily beat it to the southwest. I still can't figure out what they were doing. It was clear they were gathering, but how did they know where to meet and why so late in the afternoon! One more observation is that their crops were nearly bursting as they had been gorging themselves on some of the horde of millions of grasshoppers. When it was all over a solitary Swainson's remained atop a dead snag. I'm wondering if he or she was there from the beginning!

Part of large gathering of Swainson's Hawks near Estancia New Mexico - Torrance County