WASHINGTON — The day after a frigid, star-salted night spent tromping through the Alexandria woods with David Johnson of the Global Owl Project, and listening to the stridently mournful cries of wild barred owls that remained hidden from view, I stopped by the National Zoo around sunset to take visual measure of the birds I had heard.

The two barred, or Strix varia, owls were just rousing themselves in the outdoor enclosure, and they looked bigger and more shaggily majestic than I expected, with capes of densely layered cream-and-coffee plumage draped on their 17-inch frames and pompous, Elizabethan feather ruffs encircling their necks. Like any good royalty, they ignored me.

That is, until I pulled out my phone with the birdcall app and started playing the barred owl song. The female’s languid eyes shot wide open. The male’s head spun around in its socket by 180 of the 270 degrees an owl’s head can swivel.

With the distinctive forward-facing gaze that can make owls seem as much human as bird, the barred pair stared at me. I played the call again, the male grew bored, and I was about to put the phone away when suddenly the female — the larger of the two owls, as female birds of prey often are — pitched her body forward on her perch, lifted up her heavy, magnificent wings and belted out a full-throated retort to my recorded call.