Barn Swallows swarming again

Once again, as they have been doing for at least 12 years to my knowledge (and maybe for decades more), a huge flock of Barn Swallows is gathering here in Yamhill County. For several weeks they scatter out during the day across this part of the Willamette Valley, and then join a multitude of their fellows to roost in a cornfield during the night. This evening I watched as many tens of thousands swirled together just after sunset, and then plunged down to find a perch in the standing corn. A short video clip of a small part of the major flock can be seen at the following link. The big group was too far away to video effectively.

(Unfortunately, I discovered after posting this that it cannot be enlarged for viewing, so you really can't see the birds in motion. Sorry.)