Common Nighthawk Freakout

So we've had a common nighthawk completely freaking out in our ally the last week.  I'm not sure what's going on, I'd almost think it would be nesting, but these guys should be about to migrate from our neck of the woods.  But it started when Non Birding Bill noticed it.

Yes, I know, stop the presses: Non Birding Bill noticed one of the browniest birds out there.  Above is what a common nighthawk looks like. In some areas they are a common city bird in the summer but in Minneapolis they have had a dramatic decline. We've had only one pair successfully fledge a chick in the 14 years we have lived in our neighborhood. This summer we had a nighthawk displaying and it seemed he found a mate but then he started displaying about three weeks ago and I wondered if he was attempting to re-nest and if a crow had gotten the chick.

Sunday NBB came in after pilfering some green tomatoes from an accommodating neighbor's garden and asked, "Nighthawks are brown, right?"

"Yes," I said.

"And when they fly they have those white wing stripes?"

"Yes..."

"I just saw one in the ally and it was making this strange kind of chatter sound.  I got video of it. It landed on the wire above my head but sat along the wire," he said while trying to load his video.

"That's what they do when they perch," I said, intrigued that a nighthawk would be active in the morning daylight hours.  While NBB searched for his video, I played common nighthawk's "alarm calls near nest UT" on my Sibley app and he said, "Yeah that's the sound!"

And we've heard it two or three more times this week. One night I was soaking in the tub and I heard it, so I got out and went searching for the nighthawk.

The nighthawk alternately landed on our neighbor's driveway or circled the ally as it chittered in agitation.  I never saw a chick or heard one begging so I'm not quite sure what is causing the nighthawk freak out.  Perhaps we had an owl in the vicinity?

Here's what it sounds like (the video is terrible because it was dark out, but you can sure hear that bird):

http://www.youtube.com/watch?v=rU2hk24pjJQ&feature=youtu.be