June 1 (UPI) -- When a deceased house swift, a small bird species native to Asia, was found near the Deltaport container terminal in Vancouver, British Columbia, just a few dozen feet from the Pacific Ocean, scientists were skeptical.
But new research confirms the intrepid traveler is indeed a house swift, Apus nipalensis, and likely made the trek across the Pacific unassisted.
Scientists with the University of British Columbia and the Beaty Biodiversity Museum say the species rarely roosts on ships and would have needed to take to the air constantly to feed on insects. The tidy state of the specimen's feathers suggests the bird also wasn't trapped in the wheel well of an airplane.
The tiny bird's emaciated carcass was found along the Canadian coast in May 2012.
"Our initial reaction was skepticism that this would be such an unusual species," UBC researcher Darren Irwin said in a news release. "But by combining a review of the bird's characteristics with DNA testing, we were able to confirm that this was indeed a house swift from Asia, making this an exceptional case of vagrancy."
The bird's appearance suggested the swift barely survived its trans-Pacific journey.
"Like some marathon runners, I think this fellow finally saw land and just crashed, exhausted, at the finish line," said Ildiko Szabo, forensic ornithologist and curator at the Beaty Biodiversity Museum.
"These birds are amazing fliers and can stay airborne for months at a time, but there wouldn't have been enough insect prey to sustain him properly over the mid-Pacific," Szabo said. "The mystery is what sent him so far off course."
The mystery remains unsolved. Scientists found no evidence of trauma, parasites or disease. No obvious physical problem sent the swift fleeing home. The bird is the first and only house swift ever found in the Americas.
House swift natural range is bookended by Bhutan to the west and Japan's Honshu Island to the east. But scientists suggests British Columbia should be included, too.