A few months ago I commented on the barn swallows, well, I misidentified them (verified in a Field Guide for birds East of the Rockies). They are actually CLIFF SWALLOWS.
Pardon my mistake, but those silly birds must not have gotten the memo that there are NO CLIFFS to be had over most of Tulsa, OK. I still love watching these birds swooping and diving from their mud houses at the top of expressway pylons, skimming through the air to catch a variety of insect.
I've taken a few pictures on my walkies. The quality isn't that good due to 1) it being my phone camera, 2) I managed to gwark up my camera lens by sweating on it!
The evolution of a cliff swallow nest: