The mystery of a nearly invisible tropical pinkletink which took up residence in an Oak Bluffs greenhouse has been solved. The tree frog, originally a native of Puerto Rico and thought to be a former resident of Hawaii, was captured last week by Gus Ben David of Edgartown.

“You can’t believe how loud it was,” Mr. Ben David said. “It had a piercing sound. We just couldn’t see it.”

The biggest obstacle to discovering the frog’s identity was that it had a whole greenhouse loaded with orchids and plants to hide in, and that it sounded exactly like a singing Bob White.

Mr. Ben David received many calls over the summer from Wendy Oliver after she first heard what she thought was a Bob White living in the larger of her two greenhouses. Ms. Oliver is the owner of Frosty Hollow Orchids located near the blinker, at 45 Pachico Circle. Each night she would leave the greenhouse door open, thinking the bird would leave of its own accord. When this didn’t work she called Mr. Ben David who is used to getting calls from Islanders concerned about animals that have shown up in unwanted places. He has run the World of Reptiles and Birds park since 1995 and is a former director for the Felix Neck Wildlife Sanctuary.

“I’ve seen all kinds,” Mr. Ben David said.

Mr. Ben David said he wanted to be helpful but Ms. Oliver hadn’t actually seen anything she could report. She had only heard something singing, beginning each evening at dusk, she said.

“He’d sing until 1 or 2 o’clock in the morning,” she said. “I could be in my bedroom watching television at any time of night and he’d be singing away. It was unbelievably loud. I can’t tell you how many times I called Gus.”

On Tuesday, Sept. 4, she phoned two of her card-playing friends, Jack Sylvia and Jamie Greer, and asked them to come over and help.

“They came with flashlights and looked from about 11 p.m. to 2 a.m. in the morning,” Ms. Oliver said. “It was right in our faces, we just couldn’t see it. You would stand right in front of him at eye level and not see him. I thought I was looking for a bird. I said no way it could be a bug or a reptile.”

On the night of Wednesday, Sept. 5, Mr. Ben David arrived on the scene. He spent hours searching the greenhouse and moving plants.

“It makes an amazing sound,” he said. “I can make the sound of a Bob White and it would answer me.”

Finally he saw the real culprit, a tropical pinkletink, or to be a bit more scientific: a coqui. This is a two-inch tropical tree frog, more than twice the size of a Vineyard pinkletink, and native to Puerto Rico and considered to be an invasive species in Hawaii.

“I grabbed it,” Mr. Ben David said.

Reflecting back, Ms. Oliver said she recalled receiving a shipment of orchids from Hawaii at about the same time the greenhouse singer started serenading her through the night.

“I get plants from a lot of different places,” she said. “I think I got boxes from Hawaii in June. It was amazing to me that it made it all the way from Hawaii.”

Mr. Ben David removed the frog from Ms. Oliver’s greenhouse and took it back to his own home. But then, on that first night, Ms. Oliver found it too quiet and realized that the creature which had kept her up all summer long, had become a precious friend.

“I missed him,” she said.

So last Friday the coqui was returned to its former residence back inside Ms. Oliver’s greenhouse.

On Friday night the frog was unusually quiet and Ms. Oliver became concerned. But by Saturday evening the frog was singing again, evidently happy to be home again.

There is no worry, though, that this tropical pinkletink signals an imminent invasion of other island tree frogs.

“They can’t take the winter,” Mr. Ben David said.