Harlequin Ducks, a small sea duck that migrate inland to breed on white-water streams, have been named a species of concern. They are slow to mature and females only nest on streams where they were born. Nests are increasingly vulnerable to severe stream flows due to climate change, human disturbance and oil spills on wintering grounds. Glacier National Park boasts the highest breeding pair density of Harlequin Ducks in the lower 48 states on Upper McDonald Creek; yet biologists from throughout their range report declining numbers or shifts in historical distribution ranges.
In Banff, the pair numbers have dropped from 90 to about 25 since 1995. On the coast, males no longer molt along the British Columbia / Washington border. In response to regional concerns, a group of biologists from 11 different agencies in Canada and the U.S. initiated an international, multi-agency research project investigating local and broad movement patterns and habitat use of the birds in Western North America.
In 2016, park staff and volunteers will mark two pairs on Upper McDonald Creek with satellite transmitters (males) and geolocators (females) as part of this study. This project will allow researchers to expand their efforts within Glacier and survey streams historically known to support breeding pairs. Streams supporting pairs will be selected for trapping, banding, and marking additional pairs and chicks. Information from this study will aid in conservation efforts for Harlequin Ducks on breeding, molting and wintering grounds.