First there were the hundreds of swallows, probably Cliff Swallows, soaring and whirring about me. They were diving down to a ditch, focused on the ditch. Their energy felt ecstatic. I wondered if they were drinking water, since it was so hot out. Then they rose, a whirling entity. A few feet ahead was a pedestrian bridge, and, they flew there. As a group, they were building a colony of nests. So then, I looked back, and from this direction I could see the small muddy peninsula in the ditch, the source of their construction supplies. Soon, the penninsula was covered again with swallows. By the hundreds, they were taking mud in their beaks, and applying it beneath the overhang of the bridge, building their sturdy structures.

(Sorry that the poor quality of these pics doesn't do justice to the experience!)