I've had a few opportunities to bird in California over the past year and on occasion I was fairly certain that I had seen a few Bank Swallows whizzing past as swallows do, but I was never able to get a good enough look to be certain, having never seen Bank Swallows before.
That changed on the Fort Funston beach in Los Angeles this past May 15. I had just completed photographing a few Common Ravens on the beach. Looking inland I noticed that the sandy bank above a ridge of large, broken rocks had several holes about the size you would expect from a small bird.
Bank swallows immediately came to mind, so I scaled the rocks to get a closer look. The holes sure looked like they could be swallow burrows, but there didn't seem to be any swallows.
Eventually one showed up, but it quickly darted into a burrow before I had a chance to get a picture.
Likewise, when they left the burrows it was usually with a full head of steam.
Eventually more and more swallows started showing up until there were probably 20 - 30 flying around me. I never got a shot of one at rest as I never saw one at rest, but I was able to cross my fingers and shoot away as they streaked by or rode an air current off the shore and up the bank.
As you can see above, there were several holes, and this was just one section of the bank.