He weighs less than a ping-pong ball and isn't particularly friendly, but a vagrant hummingbird is Ohio’s unlikely new celebrity.

In the week and a half since a Calliope hummingbird arrived at a Delaware home, more than 500 people have flocked to get a glimpse of the birding mega-rarity.

"I think, only once or twice, we’ve had 10 or 15 minutes where we haven’t had someone in our yard," said Tania Perry, a birder who’s been feeding 'Cal' and corralling his human fans. "The bird is a star. I’ve seen people cry."

Encountering a Calliope, the smallest bird in the United States, usually requires booking a trip to the Rocky Mountains. The appearance of the 2-inch Calliope in Delaware marks only the second reported sighting of the species in Ohio since a spotting 15 years ago in Chillicothe.

"It is the most famous bird in Ohio right now," said naturalist Jim McCormac. "And probably the most photographed Calliope hummingbird in the world."

On Halloween morning, Perry first noticed the hummingbird's presence outside the bedroom window she keeps cracked year-round.

"I know my normal sounds," she said. "I heard something different than the usual chatter."

A birder herself, she knew exactly who to call to verify the errant visitor's identity. Then she and her husband, Corey, debated whether or not to share the sighting online and brace for a certain paparazzi stampede.

"We knew when we posted it, people would be here," she said. "How could I not share such a rare gift? How could I be selfish?"

So that evening, while their 13-year-old went out trick-or-treating, Corey Perry strung caution tape in the backyard and briefed neighbors about the impending hullabaloo.

By the following morning, first arrivals began to trickle onto their property. Then came children and retirees, van loads of Amish birders and visitors from across Ohio, Michigan, Indiana and Philadelphia. On Saturday afternoon, 40 people crowded the backyard with binoculars and outdoor photography equipment.

"For such a little creature to bring so much joy and excitement to so many people is remarkable," Corey Perry said.

The Delaware couple set up a second feeder closer to the viewing area, provided coffee for their human guests and even set up a Facebook page for the hummingbird, whose online presence is managed by Corey Perry.

McCormac, whose list of Ohio bird sightings exceeds 375, said it’s unclear how long the bird might stick around — hence the avalanche of attention.

"You learn to never hedge your bets," he said. "It’s avian stamp collecting, basically."

The species is adapted to freezing overnight temperatures, McCormac said, so the weekend cold snap is nothing a Calliope hummingbird hasn't weathered before. Eventually though, McCormac said he hopes the avian visitor will begin its southbound migration before Ohio's winter truly settles in.

Western hummingbirds, like the Calliope, have increasingly appeared far east of their normal, mountainous breeding territory.

"It’s now a really established pattern. It goes beyond vagrancy," McCormac said. "So now the million-dollar-question is why? And no one knows, honestly."

Sean Hollowell, 22, of Beaver Creek, was one of the very first to travel to the Perry home to get a look at the bird.

On Thursday, he went back for a second round and gasped along with the rest of the backyard throng as the tiny bird practiced a courting ritual by floating 50 feet in the air then diving headfirst toward the ground.

"It’s pretty unreal," Hollowell said between attempts to track the bird with his camera. "It’s like finding a needle in a haystack."

Kathryn Cubert, 58, an accountant and wildlife photographer, typically does her birding at Metro Parks or other local spots. Usually, it's a solitary activity.

"(This) makes you realize how many people do appreciate what we have," she said.