Waking Up with a Whip-poor-will

While opening mist nets this past Sunday morning at the Kiawah Island Banding Station, I was shocked to hear the song of a nearby Eastern Whip-poor-will. My first instinct was to ask one of the banding technicians near me if he was playing a recording. "Nope. You?", he responded. It wasn't me. Even though I used to have an Eastern Whip-poor-will ringtone, my phone hadn't rung, and no one else was near us. I continued to open up the nets, and again, the bird began singing from the same location. "What the heck is going on?", I asked myself. Why was this bird singing in the middle of post-breeding migration in an area where it doesn't winter?
As I pondered this non-breeding singing question, I ran into the other banding technicians who were finished opening nets. They, too, had heard the whip-poor-will. "Good. I'm not crazy or still sleeping", I sighed.
During our first net run that morning, we found the whip-poor-will in the mist net near where it was singing. This was the second Eastern Whip-poor-will caught at our banding station and by far the bird of the day.

Over the last few days, I have meditated on the question I asked myself Sunday morning when I first encountered the whip-poor-will: Why was the bird singing during its post-breeding migration?
I know that some bird species sing on their wintering grounds and even during their pre-breeding migration. But I can't recall ever reading or hearing of birds singing during their post-breeding migration.
Birds that sing outside of the breeding season may do so for one or several reasons: 1) elevated plasma testosterone levels in males cause them to continue singing, 2) to establish and defend territories on their wintering grounds, 3) to maintain social status/dominance hierarchies within the flock (for birds that flock together during migration or winter), or 4) to maintain flock cohesion.

While it is possible (isn't anything?), I am almost certain the whip-poor-will I heard will not be overwintering here on Kiawah Island, SC. Thus, it is doubtful the song I heard was intended to establish and/or defend a wintering territory.
From what I've read, whip-poor-wills form loose flocks during migration. So it is possible the song I heard may have been communicating a message of social status or presence to other flock members. (It's worth noting that we didn't catch, see, or hear any other Eastern Whip-poor-wills that morning or since then).
Perhaps the singing whip-poor-will that I and others heard was a male doing what his testosterone "instructed" him to do. A slave to his hormones.

In their book "Nightjars: A Guide to Nightjars and Related Birds", Cleere and Durney (1998) state that the Whip-poor-will (Caprimulgus vociferus) "[sings] briefly during migration".  The authors don't tell us is which migration: pre-breeding or post-breeding. Do the birds sing during both migrations?

I plan to post my observation (and question) on the relative online discussion boards and await responses. I'll keep y'all updated when I learn something new.

Rainy Day Banding #12 and 35

6-September-2014
With the threat of rain on the horizon, we decided to try and band birds anyway. The first net round showed promise for a good day of banding, as the very first net I checked had two Yellow Warblers and one Prairie Warbler. This doesn't sound like a lot of birds. And it's not. But recently it has been so slow that many rounds we only net one bird. So I was excited to see three in one net.
However, my premature enthusiasm quickly dissolved as we confronted empty net after empty net. The next few rounds also proved quiet: A Northern Cardinal here, a Painted Bunting there, one Red-eyed Vireo. It was a pretty typical, early fall migration day for us on Captain Sam's Spit.
A lack of a breeze and a whirl of persistent gnats only exacerbated the ennui of a slow banding day. Happy to flee the gnats and stretch our legs, we began another net round when suddenly the sky opened up. (The rain gods must have been listening to my prayers).
As experienced bird banders, we knew that we must get birds out of nets and close the nets as soon as possible. Fortunately, there was only one bird to extract (a recap Carolina Chickadee, of course!), and we were able to close the nets rapidly and without incident.
And then we played the waiting game.
The rain dropped a lot heavier and lasted a lot longer than I thought it would.
Normally, we all maintain pretty good poker faces on slow days. But this Saturday morning, no one attempted to hide his or her readiness to go home. One could almost read the comforting thoughts of hot coffee, showers, brunch, and couch sleeping on our faces. The unanimous decision to pack up and head home was made, and within 40 minutes, we were all enjoying our respective lazy, Saturday morning rituals.