As temperatures cool and leaves start to change, birds begin their annual migrations to winter habitat. Among those flying through Montana skies this fall are brightly colored harlequin ducks. Researchers have documented population declines of the birds in recent years, but no one is quite sure why.
New research has been uncovered to determine the best way to find and count harlequin ducks in an effort to save them.
Holli Holmes, a graduate student at the University of Montana, stood on the shoreline of a rolling stream along the Rocky Mountain Front. She peered through her binoculars looking for harlequin ducks on one of her last surveys before they head west to winter on the coast.
“They might look like a rock right now, like, they're sort of rock size, rock shape and rock colored in these rocky streams,” Holmes said.
These unique waterfowl breed along fast moving whitewater in the intermountain west. In Montana, their breeding range follows mountain streams from northern Yellowstone National Park up into Glacier.
Data from the National Audubon Society projects that under warming conditions of 1.5 to three degrees Celsius harlequins could lose anywhere from 43-65% of their summer range as they move further north.
Holmes is leading a collaborative study funded by Glacier National Park, the U.S. Forest Service, Fish, Wildlife and Parks (FWP) and several conservation nonprofits to figure out the best way they can find and count these rock-looking birds in their breeding habitat.
“We came together, the different biologists in the region came together, to say we can pool our resources to do a really intense studying for a couple of years to try and figure out what the best methods are,” Holmes said.
Historically, biologists have relied on foot surveys, hiking miles up a stream looking for these ducks. It’s a labor intensive task to say the least and often risky.
“Some of the most downright suffering I've been a part of as a biologist has been on duck surveys,” Dave Kemp, wildlife biologist for the Forest Service in Choteau, said. “Where you are wet from head to toe all day, every day and the temp is floating above freezing during the spring. And it's just, you're waiting to crawl into a wet sleeping bag or get back to a cabin and maybe you can get a fire going to heat yourself up, all in the hope that you find two ducks in five days.”
Kemp is one of the collaborators on this project. He’s using Holmes’ methods to survey for harlequins along the Helena-Lewis and Clark National Forest. It’s a remote area where just getting to a survey site can mean a 20-mile mule pack into basecamp. But he said the trek is necessary to get the answers they need.
Population counts at the ducks’ winter habitat have shown declines in recent years, but it’s not clear what’s causing that.
“What happens in each of their stopovers, or where they're going to winter, or summer, or go through transitions between those areas, is important for how they persist over the long term,” Kemp said.
Holmes said understanding what the population does in the breeding season is a crucial piece of the harlequin duck conservation puzzle.
“It's opening the door to just finding better conservation methods for studying these species that just live in these really harsh environments for biologists and people to get to,” Holmes said.
The project involves setting up game cameras alongside streams, hiking miles up and down a stream looking for ducks and a newer technology called environmental DNA that actually detects whether harlequins have swam in a stream.
“They're in water, they're in streams and then we're looking for DNA within the water column. So the DNA can come from anything that's sloughed off the animal. That could be like poop, that could be sweat, that could be saliva, that can be feathers,” Holmes said.
eDNA, as it’s commonly referred to, has mostly been used to detect fish in bodies of water. But, harlequin ducks are better at swimming than they are at walking, so Holmes wanted to see if this technology could be used on them too.
She pumped five liters of water through a small filter, about the size of a cracker and the thickness of a sheet of paper.
The filter then goes to a genomics lab which can use the sample to tell whether or not there’s harlequin duck DNA in any given stream.
Data collection like this could help save biologists, like Kemp, valuable time and resources while meeting conservation goals.
“I think that's a benefit for sure. And so hopefully it keeps going and we find out something useful from this project, which I'm sure we will, I just don’t know what that is yet,” Kemp said.
With the season ending, Holmes will spend the winter and spring going over images from her game cameras and analyzing eDNA samples. That data will help her, Kemp and other wildlife managers decide what future monitoring efforts will look like and hopefully keep harlequins successfully breeding in Montana for generations to come.
