The haunting sound of the Wilson’s snipe is a familiar one around this province’s bogs, fens and wet meadows.
“More people have heard rather than seen the bird – which is listed in The Dictionary of Newfoundland English as a snite or twillick,” said Dr. Ted Miller, professor and acting head of the Department of Biology, Faculty of Science.
He says the bird’s distinctive bleating or winnowing sound is produced by the outermost spread tail feathers of male birds as they descend rapidly in aerial displays over their breeding territories.
That unique sound, which is different from that of the common snipe of Eurasia, was used as scientific evidence in 2002 to recognize Wilson’s and common snipes as separate species.
That led Dr. Miller and his colleagues to wonder if there were other hidden snipe species out there.
“The other 18 species in the world had not been investigated, but 17 of them also have aerial displays and all differ strikingly from one another in the number, size and shape of their tail feathers,” he said.
The researchers began with the South American snipe.
They suspected it might be two separate species because there were two distinct geographic races of the bird, which are separated in Argentina by the Monte Desert.
It also breeds over an unusually large and ecologically diverse geographic range – from tropical areas in northern South America to southernmost Patagonia east of the Andes, and north to Santiago, Chile, west of the Andes Mountains.
North vs. south
In 2004 the team began recording breeding birds in various locations in South America and complemented their samples with recordings by colleagues and other recordists, so their final analysis was based on recordings from almost every South American country.
“My early sound recordings were of the southern race in Patagonia Chile,” said Dr. Miller. “Years later, when I first heard a South American snipe of the northern race calling from the ground in Paraguay, I did not recognize it because it sounded so different.
“My host, a Paraguayan ornithologist, was looking at me oddly and when I asked what was wrong, he said, ‘Well, aren’t you going to record it?’ But I had thought it was a frog.”
He ultimately discovered all of the northern bird’s mating sounds differed enormously from those of the southern race and subsequently determined these differences held through the ranges of the two races.
Reproductive traits invariably differ across species, even closely related species. For this reason, such traits are invaluable for detecting new or unrecognized species.
Their research on the South American snipe did indeed reveal species-level differences in mating displays between the two geographic forms.
The differences were so great that even a brief sound recording of a bleat or call could be unequivocally assigned to either the northern or southern bird.
“It was startling to us that legions of birdwatchers and ornithologists who have been active in South America over many years had rarely remarked on this difference,” said Dr. Miller.
“One of my fellow researchers on this project is a well-known ornithologist who wrote a book on the birds of Chile. He said he had been suspicious that the South American snipe was two different species, so it was nice to join forces with him to actually prove it.”
Additionally, they found that tail-generated sounds differed even more than the bird’s calls.
Dr. Miller believes that it is only the second time that geographic races of a bird have been elevated from subspecies to species ranks using both vocal and non-vocal displays.
“That was one of the most exciting things about this work, because it’s hardly been done. A lot of birds make sounds when they fly or take off, but the sounds really become elaborated in a lot of hummingbirds and that’s the only other group in which wing or tail sounds plus calls have been used to reveal a new species.”
More to discover
Dr. Miller is currently building on this project by analyzing sound displays of all the world’s known snipe.
He believes there are more hidden species yet to be revealed, and relationships between some species that are, as yet, unknown.
“We’re certainly finding some surprises. We haven’t worked through all the material yet, and there’s a lot of it. There are also still holes in the collection, particularly within Africa. It’s a vast continent and we have some recordings from the north and some in the south, but there are a lot of places in between that we don’t.”
But first, there is still one recording in South America he is determined to obtain.
“We’re missing one, which is the one I went to South America to get in the first place,” he said. “It’s the Fuegian snipe, but the problem is it lives on remote sub-Antarctic islands, which are dangerous to get to because of steep seas. But we’ve got all the others, so we’ve just got to figure out a way to get it.”