The 2018 Breeding Season Begins with a Surprise – An Interloper at the Nest Box!

Ares arrived at the nest box at around 6:15 AM. Astrid arrived on the north face of the State Building at around the same time. About 15 minutes later he dashed off after prey. He returned a short while later with a bat in his talons. As far as we know, this was the first bat of the season. Unfortunately, the bat was still alive, but Ares dispatched in within a minute. We believe his plan was to gift it to Astrid, but she showed no interest in coming over to accept it. Instead, she stayed right where she was. We learned long ago that Astrid is no fan of bat flesh. Ares left with the catch and probably stored it somewhere. A few minutes later he came back to the box without the food. Given the unseasonably mild temperatures today (with temps in the 60’s), Ares seemed especially keen to get Astrid over to the box. He made several visits over the next two hours, but she wasn’t interested in coming over. At about 8:30, Ares gave some alarm calls from the box, but they were somewhat subdued calls, so we weren’t that concerned. Ten minutes later two falcons were performing a ledge display at the nest box. The “dance” was atypical. It started with some raucous beaking and then Ares stood back while the female did fancy side-stepping moves in the center of the box. Soon the female moved out onto the box’s perch. It wasn’t Astrid! It was an unknown adult female Peregrine with markings similar to Astrid’s. One obvious difference was that she was a banded bird. She was acting like she owned the place – walking on the box’s perches, strutting out onto the east veranda, and at one point she even jumped up onto the roof of the box. All the while, Ares was peering at her from inside the box and Astrid was nowhere to be seen.

Why wasn’t she challenging this intruder? Normally she would be hazing such an audacious stranger. We didn’t know if Astrid had fought with this interloper or not. When I went down there about an hour later I saw three Peregrines zooming around in the canyon’s airspace. The winds were particularly strong today and the maneuvers of the falcons were quick and quite spectacular. The three were lightly sparring and it did seem as though it was Ares that was more aggressive in pursuing the intruder. I was very surprised that it wasn’t Astrid taking the lead since it was a female interloper. But for all I knew, Astrid had already done her share of persuading. Without any clear combat taking place, suddenly the stranger was gone and it was only our home pair diving and soaring through the canyon. At one point they converged at the box, but there was no ledge display. Instead Astrid took to the air again and spent a considerable amount of time scuttling the local Pigeon flock and putting on a one-falcon air show. After about 15 minutes, Ares left the box and joined her in the sky.

At noon, Ares was at the box again and after perching for while he abruptly issued some “kack” type alarm calls, but neither bird left their perches. He probably saw a raptor (maybe a migrant) way off in the distance, and possibly sailing on the strong winds. A half-hour later he flew up to Astrid who was perched on a high ledge on the State Building. He hovered over her for a few seconds as if mating, but there was no contact between them. At 2:00 PM, Ares brought an unrecognizable hunk of prey to the nest box. This time Astrid came right over and took it from him. She brought her gift over to the hotel and devoured it. Later the pair was seen perched near each other on the north face of the State Building. Will we see the intruder again? Perhaps. Since she is a banded falcon, we hope we can read the numbers off of her bands and find out where she came from. All we know now is that she came from a New York State nest site.