DNA Tests Point To Extinction Of Arctic Bird Populations

Two populations of rock ptarmigan from opposite ends of North America are in danger of disappearing permanently if conservation and management practices aren’t changed, says Biology Professor Bob Montgomerie.

His research team uses DNA analysis to show that both populations – one in Newfoundland’s highland ranges and the other in Alaska’s Aleutian Island chain – are genetically distinct from all other rock ptarmigan and should be considered separate species.

“Traditional classifications often fail to capture the diversity and evolutionary history of organisms below the level of species,” Dr. Montgomerie explains. “If we consider these populations to be distinct species, they would deserve immediate preservation under the Species at Risk Act, changing management policy on both islands and hunting practices on Newfoundland.”

Currently there are 19 “endangered” and seven “threatened” bird species in Canada. Three distinct bird species are known to have become extinct in North America since 1900.

The study will be published in an upcoming edition of the Canadian Journal of Zoology. Also on the team, from the Queen’s Biology Department, are researchers Karen Holder and Vickie Friesen.

Although not endangered in other arctic regions, the rock ptarmigan populations identified in this study are definitely at risk, say the researchers. In the Aleutian Islands this is due to foxes that were introduced in the 18th century for fur farming, while in Newfoundland the birds are hunted by people as small game.

“Reclassification of these two populations should immediately move them into the ‘species at risk’ category, and thus afford them the protection they need,” says Dr. Montgomerie.

In another rock ptarmigan study with Drs. Holder and Bruce Lyon of the University of California, Dr. Montgomerie is resolving the mystery of why ptarmigan males delay molting from their winter plumage each spring: an unusual pattern in birds. When the snow melts away from the tundra, their white winter plumage stands out against the darker landscape, making them much more conspicuous to predators. (Female ptarmigan change to a mottled brown colour a month earlier than males.)

The researchers conclude that brighter-plumaged males are more attractive to females and thus have more mating opportunities, leading to greater reproductive success. Male ptarmigan will soil their feathers, providing instant camouflage, once their mates have begun laying eggs – and this camouflage is reversible if the female loses her eggs or is unable to fertilize them.

Dr. Montgomerie’s arctic research is funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Arctic Institute of North America, and a Canada Council Killam Research Fellowship.