Chasing Canvasbacks

Graduate student Rich Cain tracks hens and broods to determine duckling survival

By Paul Wait

Gravel crunched under the truck’s tires as Rich Cain pulled over atop a Manitoba hillside adjacent to a dense stand of aspen trees. To a hunter’s eyes, the spot looked much more like a great place to find a ruffed grouse, turkey, white-tailed deer, or black bear than it did a haven for canvasback ducks—no wetlands were visible.

Sensing my doubt, Cain reassured me that down the hill on the other side of the woods, the technicians working on his research project had found and marked a canvasback nest containing a clutch of eggs nearly ready to hatch.

“It’s certainly an unusual spot,” said Cain, a master’s degree student at the University of California–Davis. “The wetland is surrounded by trees, but the canvasback hens seem to like it. This nest should be about to hatch, so it’s time to catch the hen and put a nasal saddle on her.”

Cain slid on waders, grabbed a circular wire cage from the truck, and disappeared into the woods. A short trek through the early June leaves opened into a couple-acre wetland. Trudging through the deceptively waist-deep tangle of last year’s cattail litter, Cain stopped to study his phone after discovering a nest bowl full of canvasback eggs in his path.

“This isn’t the nest we’re looking for,” Cain declared. “According to my map, the one about to hatch is another 30 yards ahead. But it looks like an active canvasback nest, so we’ll come back to it.”

A few steps later, a hen canvasback took flight, arcing low along the edge of the wetland to get enough air to clear the trees. Cain located the target nest, delighted to find a bent-vegetation bowl filled with warm, olive-green canvasback eggs.

“This is a nest with no parasitism, just seven canvasback eggs,” Cain said through a slight smile as he lifted an egg to his ear.

Nest parasitism, he explained, is common for canvasback nests on the Canadian prairie breeding grounds, so much that it’s notable when a nest contains only canvasback eggs laid by a single hen. Redhead hens are the primary culprit, often parasitizing a nest by laying their eggs in another hen’s nest. Intruding hens often roll eggs out of a nest before depositing their own. In most cases, the parasitic eggs won’t hatch because they aren’t in synch with the rest of the clutch.

“We can see some cracking, and the ducklings are starting to break through the shells,” Cain said. “It’s been incubated for probably about 24 days. It’s really neat to put the egg up to your ear and hear them chirping in there and breaking through. We’re going to trap this hen and put a nasal saddle on her, and this brood will likely be hatched out within 24 hours.”

After placing the eggs back into the nest bowl and gently covering them with cattails, Cain staked down the wire cage trap directly over the nest. If the device worked as intended, the hen would soon return and trip the trap to close herself safely inside.

Cain returned to the newly discovered nest, checking that hen’s eggs by holding them up to the sunlight and peering through the shells using a cylinder to block out light from the sides.

“Nine or 10 days,” he declared after eyeballing several eggs through the rubber tube.

The process of candling eggs allows trained technicians to determine the development stage of the embryo and estimate when it will hatch.

Brushing aside buzzing mosquitoes, Cain logged the data for this new nest into his phone, covered the eggs, and started the slog toward his truck.

“We’ll go check a nest at another location and come back here in an hour to see if we’ve caught our hen,” he said.

Send in the Drones

Cain, a graduate student advised by Dr. Kevin Ringelman at UC–Davis, began his two-year master’s degree project last spring at Delta’s Minnedosa Research Station. Cain is studying brood survival in canvasbacks, particularly to understand detection factors that could allow waterfowl managers to more accurately estimate duck production.

Cain’s research team includes four technicians tasked with locating duck nests, determining when they are due to hatch, and then searching for broods. But instead of beating through the cattails to find nests, Cain and his technicians are using drones equipped with thermal-imaging and optical cameras to find and check duck nests.

Canvasbacks nest over the water in semi-permanent wetlands. Generally, hens choose a spot in a dense stand of cattails near deeper water. The hen will bend cattails over to form a nest bowl just above the waterline.

Once a canvasback nest is located by drone, Cain initiates a “foot visit” to count the eggs and determine the incubation stage. After the nest is catalogued, subsequent check-in visits are conducted using the drone until the nest is either abandoned, destroyed by predators, or nearly about to hatch.

Delta Waterfowl researchers have been using drones to find duck nests since 2017, when Delta graduate students Jacob Bushaw and Roald Stander conducted nest detection research in Manitoba by flying drones. Drone and camera technology continues to advance, and Delta continues to innovate by using these tools to improve the efficiency and accuracy of scientific methods to study waterfowl.

Cain’s research is one of three current Delta projects using drone and camera technology to detect broods. Grant Rhodes, another graduate advisee of Ringelman, is working toward a Ph.D. studying blue-winged teal in Saskatchewan and Manitoba. Jack Johnson, a master’s degree student at the University of Wisconsin–Stevens Point advised by Dr. Ben Sedinger, will be studying brood survival and movements of mallards, gadwalls, and blue-winged teal in South Dakota.

“We’re trying to learn about brood detection rates by using a combination of nasal saddles and VHF radios, so we can compare them to the detection rates we’d encounter with unmarked broods when we develop normal, operational brood surveys,” said Dr. Chris Nicolai, waterfowl scientist for Delta Waterfowl and manager of the organization’s research program. “We’re doing this research work for the benefit of all in the waterfowl management community.”

In addition, Cain’s research builds upon nearly a century of Delta canvasback studies that stem back as far as the 1930s, when industrialist James Ford Bell founded the Delta Waterfowl Research Station in Manitoba. Starting with H. Albert Hochbaum to Dr. Michael Anderson to present-day researchers, Delta has amassed an impressive and important body of scientific discovery on canvasbacks.

Nasal saddles are attached using a thin metal rod that falls harmlessly off the duck after a couple months.

Nasal Saddle Markers

Just over an hour after Cain set the trap, we rolled to a stop next to the secluded woodsy wetland. Cain hopped out of the truck and spread out a landing pad for a drone. Within a minute, he’d flown the drone-mounted camera high above the canvasback nest.

“She’s in the trap,” he declared.

The discovery drone landed, Cain bounded through the woods and slogged toward the caged hen. He carefully plucked the hen from the trap, cradling the duck as he walked toward the edge of the wetland.

Working from a plastic tote, Cain pulled pliers and a bright yellow nasal saddle from the toolkit. He aligned the holes of the form-fitted plastic nasal saddle with the hen’s nostrils, then inserted a crimped metal rod and tiny washers on each end to keep it in place.

The hen was given the nasal marker—think of it as a license plate—adorned with a large letter “H” with a smaller forward slash “/” symbol designation.

The symbol identifies the block where the duck nest originated, while the larger letter or number identifies the individual marked hen.

“We have attached a unique nasal saddle on this canvasback hen that we’re going to use to identify her and her brood,” Cain said. “This is a young hen with her first brood. Her eggs are hatching today, so we’re going to try to come back to locate her and her brood tomorrow and as frequently as possible after that. We’re trying to learn where they’re moving, how many ducklings are surviving each day, and really just learn as much as possible about this specific brood.”

Cain secured the nasal marker, while technician Leighann LaFrance, a graduate of Louisiana State University, recorded data and removed the trap from the nest.

“These nasal saddles are meant to fall off in a relatively short period of time,” Cain explained. “They’re just going to stay on long enough for us to get the information we need with her and her ducklings moving around in the next month or so. Then the nasal saddle will fall off and won’t be a long-term burden for this hen.”

LaFrance took the bird from Cain, confidently carrying “Canvasback H/” deeper into the cattails to release the hen so she could tend to her nest of hatching ducklings.

Tracking Broods

From April through July, Cain and his crew located 411 duck nests. Of those, 203 were made by canvasbacks.

Predators take a heavy toll on nesting ducks, so many of the nests were destroyed or abandoned before they could hatch. Still, Cain put nasal saddles on 92 canvasback hens. Of those hens, 47 of them—just over half—successfully hatched.

“It was exciting to mark that many,” Cain said during a November 2024 interview. “It felt good, and the goal was to mark 40 to 50. There was a good nesting effort last spring.”

Of the 45 unsuccessful nests, Cain determined that 14 were eaten by predators. The cause of failure was unknown for the remaining nests.

“We marked them around 20 days of incubation, so they only had to make it a few more days,” Cain said. “To make it a few more days successfully, it was about a 50/50 chance.”

Ultimately, the researcher aimed to track as many canvasback broods as possible during their first six weeks of life. Cain’s crew was able to find 35 of the 47 broods at least once after they’d left their nests. The study protocol was to locate individual broods once a week for six weeks, but Cain said technicians observed some broods much more often. One marked hen and brood was observed 14 times over 26 days.

“If you’re flying over a pond, you’re not going to not look for the brood,” Cain said, noting that canvasbacks clearly favored a couple of ponds. “It was exciting for us to see four or five marked broods on one pond.”

The crew tracked some broods for more than 30 days, but the average time tracking marked broods was 14 days.

“That isn’t bad,” Cain said. “It’s the critical time we want to know about—the first two weeks. We want to know what survival looks like during the first two weeks.”

The observation of one hen canvasback brood left Cain surprised.

“With one brood, we know for sure five ducklings hatched. We saw them once, and it was five ducklings. We saw them again, and it was still five. We saw them again, there were seven. We saw them again, there were 10. We were like, ‘What is going on?’ There was no other hen around and no other brood nearby. It makes you wonder how much of that is going on. We talk about duckling loss and duckling survival. There’s a possibility that the ducklings just go with another brood. The broods swim together and then swim apart and both broods are a different number now.”

Watching canvasback ducklings grow up on the Manitoba prairie fascinated Cain, a California native.

“It’s like all they do is eat,” he said. “They’re just swimming around munching on flies. There were some ponds with bugs swarming everywhere. Those ducklings were just like super predators swimming around eating everything. It’s really cool to see that behavior.”

Goals for 2025

When spring blooms on the Canadian prairie, Cain will return to Minnedosa for another nesting season. Although he’s thrilled to have marked 92 canvasbacks during the first year of research, Cain has set a loftier goal for 2025.

“If conditions are right, and there’s a good nesting effort and good canvasback numbers and all the ponds are full, I’m hopeful we can top 92 by a lot,” he said. “I want to have a big sample size and still be able to follow all of the marked birds.”

Now that he knows the terrain, landowners, and areas canvasbacks prefer, Cain expects work to get off to a fast start this spring.

“To have a big sample size, you have to find a lot of nests. We have to be really efficient and work really hard to find nests early—like in April and May,” he explained. “Canvasbacks are early nesters, so getting after it super early will help us the rest of the summer. Finding nests early is much easier because the emergent cover hasn’t sprouted yet. They’re just glowing from hundreds of yards away (with the drone). They’re in the wide open. When you’re searching for them in June and July, they’re so covered up there’s a slim chance to find nests.”

Until spring, Cain is evaluating Year 1 study data and reviewing all previously published studies on canvasback brood survival and movements.

John W. Childs

“The project is unique just because of the drone technology we’re using,” Cain said. “No one will have done it this way. But going back and looking at literature, I know Mike Anderson has done a similar study on foot, so I can compare results using different methods.”

Cain’s 2024 research season has prompted new questions, too: How many of the 92 canvasbacks he marked last spring will he encounter again? Where will broods go this year? Can we use drones even more efficiently to cut down foot visits to nests?

“I’m excited to get back up to Minnedosa and get started again,” Cain said.

Paul Wait is senior manager of communications for Delta Waterfowl.

Keeper of the Canvasback

Delta Waterfowl is deeply grateful to John W. Childs—a dedicated board member, committed conservationist, and passionate duck hunter—whose generous support has advanced Delta’s canvasback research in Manitoba for more than a decade.