Bull snake "fishing" for cliff swallows

I got this email forward from my father-in-law today. This begs to be shared.

Here is the description from the photographer (apparently Adam S. Johnson of Great Falls MT - PS if you're out there, let me know if you've posted these photos elsewhere, I'd love to link):

I pulled over at the Loma bridge fishing access site just outside of the UMBNM north of Fort Benton MT on Sunday afternoon around 4:30PM to photograph the Cliff Swalows tending thier nests. What I found was an enormous Bull Snake fishing for Cliff Swallows from 30 feet above the racing Missouri River. I observed it for over 2 hours slink in and out of about 5 nests consuming the chicks. Bulge after bulge runing down it's body. Then snap, he grabed one of the adult swallows who had dared to swoop by to pester his dining. When it had had its fill it kicked itself free and dropped into the rushing river. It was a truely incredible behavior to observe and magnificent specimen.