FWP has released the following report by Kalispell biologist Chris Hammond:
Here’s an excerpt:
“Harlequin ducks are small sea ducks that winter on the coast and migrate inland to breed on fast-moving streams where the female hatched. They are slow to mature and reproduce, exhibit a boom or bust reproductive pattern, and are vulnerable to climate change. They typically choose nest sites within 1 meter of the water’s edge and initiate incubation as stream volume starts to recede after peak spring runoff. Stream flow severity—higher stream flow, greater number of peaks, and elevated highest peak—has increased in recent history. These processes are also predicted to become worse due to climate change, potentially flooding out an increased number of harlequin duck nests. In the event of a nest failure there is no chance for a second clutch because males migrate back to the coast once the female initiates incubation. Females show strong nest site fidelity and are only known to breed in the drainages where they hatched. Montana’s first statewide survey effort for harlequin ducks was conducted in 2014. Fish, Wildlife and Parks and its partners documented 31 hens and 115 chicks. In 2015, we attempted to duplicate our 2014 effort, but a bad fire season limited access to several areas and the survey was incomplete. In northwest Montana, Glacier National Park has consistently surveyed for harlequin ducks since the late 1980s and that population appears to be the only population in the western continental U.S. and western Canada that has not observed declines.”
