A pair of conjoined barn swallows, attached at the hip by skin and possibly muscle tissue, will be sent to the Smithsonian Institution for study and examination, Arkansas wildlife officials said.
If confirmed, officials say it could prove to be an incredibly rare find – a set of conjoined twins among birds.
“I can't even say it's one in a million – it's probably more than that,” said Karen Rowe, an ornithologist with the Arkansas Game and Fish Commission. “There's just very little to no records of such a thing.”
The birds, found by a landowner in White County on Thursday, fell out of a nest as a healthy sibling flew off to learn how to hunt with its parents, Rowe said.
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The birds first appeared to have only three legs, but further examination found a fourth leg tucked up underneath the skin connecting the pair.
Rowe said the landowner likely kept the birds for a day before calling wildlife officials. By the time officials arrived, the two birds refused to eat.
One of the birds died Friday morning, and a veterinarian later euthanized the other.
While conjoined twins have been documented in humans, other mammals and reptiles, finding conjoined birds is difficult, as they likely die before being discovered, Rowe said. X-rays of the pair found each bird was fully formed, Rowe said.