This past weekend, Brooklyn birders spotted a New York first: a zone-tailed hawk, a rare raptor typically seen only in the southwestern U.S. or Central and South America.

State-first sightings are a big deal to birders, and this one set the avian world atwitter. But to some, this record was expected. Hawkwatchers from Virginia to Nova Scotia have observed a zone-tailed hawk in four of the last eight years. It’s hard to say how many individual birds these records represent, but the species has been expanding its range in North America over the last 30 years, according to Cornell Lab of Ornithology.

On April 2nd, a group of bird-watchers congregated along one of Green-Wood Cemetery’s tree-lined streets — the graveyard is popular with quiet-seeking birders. They spotted a flock of raptors, including turkey vultures, one of the cemetery’s resident red-tailed hawks and a bird that looked like a cross between the two. The mysterious visitor had a hawk’s outline and a turkey vulture’s coloration of black with pale wing feathers. The group began snapping pictures.

Puzzled, Brooklyn birder Angela Panetta immediately messaged a photo of the bird to her friends and passed it through a bird identification app. The app suggested zone-tailed hawk. Once the friends realized what it was, they sent back expletives — it was definitely a zone-tailed hawk.

“I started freaking out,” Panetta said. “Being a beginner birder, I never thought I would be one of the people who saw something that’s never been reported in the state before.”

The bird departed quickly, chased away by one of the cemetery’s resident red-tailed hawks before heading across the New York Harbor, where a Staten Island birder also spotted it. No one has seen the hawk since, and it likely migrated northward, as a zone-tailed hawk acting normally in its usual range would.

Zone-tailed hawks are poorly understood, according to Cornell’s Birds of the World, with only a few hundred pairs breeding in the southwestern U.S., though sightings are more common in Panama and Costa Rica plus eastern Brazil, Venezuela, Peru, and elsewhere. For anyone searching the skies here, look for turkey vulture-esque appearance and behavior — teetering flight, black plumage with white wing feathers, and wings held in a slight V-shape — but with a bright yellow beak and a white band across the tail. This mimicry might help them ambush predators who otherwise wouldn’t worry about nonviolent vultures.

While the sighting was a shock for New York birders, it’s not totally unprecedented, explained Tom Johnson, a birding tour leader for Field Guides and former songbird counter at the Cape May Bird Observatory. The species’ range has slowly been expanding north, and there’s an increasing pattern of zone-tailed hawks showing up out of their range across the whole United States, including the Northeast, he said. Johnson also wondered whether the species’ similarity to the common turkey vulture has caused others to go unnoticed.

“The reality is that in most of the zone-tailed hawk’s range, it occurs at low density and is uncommon and patchily distributed, so we don’t really have a good handle on what they’re doing in terms of their movements,” said Johnson.

Panetta said that another one of the finders plans to file a sighting report to the New York State Ornithological Association’s Avian Records Committee so that the episode enters the official record. Hawkwatchers across the Northeast are on high alert hoping to get a chance at seeing this same bird at their local spots, said Brian Rusnica, president of the Eastern Massachusetts Hawk Watch organization. In previous years, birders were able to follow the movements of individual zone-tailed hawks across multiple sites.

So, eyes up, because you never know what kinds of migrating birds might fly over.