I've been celebrating my return to Portland by going out and doing things I was too busy for when I lived here before. Last night I finally made it out to see the vaux's swifts (Chaetura vauxi) at Chapman Elementary School. Every September evening--and even into October--they arrive en masse at dusk to spiral into the chimney for a safe place to sleep.
This phenomenon started in the 1980s after the wholesale clearcutting of old-growth forests removed most of the natural hollow snags the swifts roost in. The school stopped using their heating system while the swifts were there, and two decades ago Portland Audubon (now Bird Alliance of Oregon), who organizes the swift watches every year, donated a new heater that didn't make use of the chimney, which is now solely maintained for the swifts.
Enterprising predatory birds, like Cooper's hawks (Astur cooperi) and peregrine falcons (Falco peregrinus), will perch at the mouth of the chimney and pick off swifts for an easy meal. Last night there was a Cooper's taking up the spot, and you could tell the swifts were quite wary, not wanting to risk flying too close. I watched this hawk catch three swifts, and managed to get the last one on video, seen here; it flew off shortly thereafter, and the swifts immediately dove into the chimney.