This may sound strange, but every fall I see Swainson’s Hawks (and some Red-tailed and Broad-winged Hawks) migrating after sunset along the Wasatch Mountains in Utah and Goshute Mountains in Nevada. I’m not the only one, previous observers at the Goshutes are aware of this, and others who have visited ridge sites in the West have witnessed it. Buteos are generally thought to migrate during peak thermal times (late morning to late afternoon), but this is not the case along ridges, as it is quite common to see them moving in the darkness in late September through early October. I assume they feed early morning, and fly all day including after sundown if the updrafts are still sufficient.
I do see many Swainson’s flying after dark that settle in the Pines before it is pitch-black though. One night (after sundown) at the Goshutes, a kettle of 10 Broad-winged Hawks settled into a group of trees off the east side of the ridge. The next day at sunrise, the same group of 10 took flight from the trees. I know it was the same group because it included 2 DARK BIRDS (an adult and a juvenile), a neat sighting anywhere!
Labels: migration, night migration, raptors