They're not seabirds, but I got to experience the Portland swifts for the first time tonight and they were spectacular. This article answered a few questions about what they're up to.
Vaux’s Swift roosting ritual at UO demonstrates adaptation, congregation — and sacrifice
It’s the time of year when thousands of small birds called Vaux’s Swifts swarm around a defunct chimney on the University of Oregon campus in Eugene. Their presence results in a constant, high-pitched chittering. And like the pop star with the same last name, these Swifts have legions of fans.
opb.org