Published July 06, 2008, 12:00 AM

GPS tracking will make it hard for these mallard hens to hide

A broad-based group of waterfowl researchers, including state and federal biologists from the Central and Mississippi flyways, are teaming up on a project to put GPS transmitters on 25 mallard hens this fall in North Dakota and Saskatchewan.

By: By Brad Dokken Grand Forks Herald,

A broad-based group of waterfowl researchers, including state and federal biologists from the Central and Mississippi flyways, are teaming up on a project to put GPS transmitters on 25 mallard hens this fall in North Dakota and Saskatchewan.

The study will focus on midcontinent mallards, whose breeding, migration and wintering areas lie in the Central and Mississippi flyways. The goal is to learn more about the habitat the hens use during the fall migration, a time of year when the birds migrate thousands of miles from their breeding grounds in the northern U.S. and Canada to southern states.

The solar-powered transmitters, which cost about $3,500 each and are accurate to within a few meters, also will shed light on where the hens go and what they do during the spring migration. Weighing less than an ounce, the GPS transmitters can be programmed to send four to six signals a day to a database, where researchers can download the latitude and longitude coordinates to determine the birds’ whereabouts.

The GPS units provide more precise locations than traditional radio-telemetry equipment.

“It’s not only where they go, but where they go during any day of the year,” said Steve Cordts, waterfowl staff specialist for the Minnesota Department of Natural Resources in Bemidji. “In the past, we could catch breeding mallards and follow them for three months or follow them on their wintering grounds for three months, but that transition time in fall and spring, we just don’t know.

“We know from band recoveries where they tend to die and where they were banded, but that’s two locations [in a year] instead of six locations a day over the course of a couple of years. That’s the potential here.”


According to Cordts, the upcoming project is a continuation of research that began four years ago in Arkansas, where biologists have attached transmitters to more than 175 mallards, including 30 this past winter.

That project, Cordts said, resulted after hunters in Arkansas began wondering why duck hunting success had declined after several good years.

“They had the birds available on the Web, and hunters could look at them” to track their locations, Cordts said. The Arkansas Game and Fish Commission still maintains the mallard-tracking Web site.

Researchers also fitted three mallards with transmitters at Thief Lake Wildlife Management Area in northwestern Minnesota in April 2006, using surplus units that became available from Arkansas.

One of those ducks, a mallard drake, is still alive, Cordts said.

Minnesota and Arkansas both are in the Mississippi Flyway.

Cordts said the Arkansas project, which mainly sought to answer the “where are the ducks?” question, caught the attention of a Mississippi Flyway duck migration committee, of which he is a member.

The Central Flyway became interested last fall, Cordts said, and that set the stage for the upcoming project in North Dakota and Saskatchewan.

Among the other partners in the project are the U.S. Fish and Wildlife Service, Ducks Unlimited and the Natural Resources Conservation Service. Cordts said the NRCS got involved after the GPS route of one mallard showed it using several wetlands restored through the federal Wetlands Reserve Program, which the agency administers.

“It’s a sample of one, but it provided what they hoped it would provide as far as habitat for breeding ducks,” Cordts said. “Here you have more or less kind of a random bird documenting use on restored wetlands for the purpose of migration behavior.”

Cordts said everything appears to be on schedule for this fall, although several logistical details remain to be worked out.


Helping to iron out those logistics will be Mike Johnson of the North Dakota Game and Fish Department and Ron Reynolds of the U.S. Fish and Wildlife Service in Bismarck. Both are Central Flyway representatives involved with the project.

“I think the real value is in monitoring birds during their migration in the fall, to see how they use different types of migration habitat, and how certain characteristics of landscape they’re using might impact their survival,” Reynolds said.

That could provide managers with information to duplicate those landscape features, if there indeed is a correlation to survival, he said.

Reynolds, who is project leader for the service’s Habitat and Population Evaluation Team, said the study attracted interest from Central Flyway states, in part because the Prairie Pothole Region in the Dakotas and southern Canada produces many of the mallards that migrate along the Mississippi Flyway each fall.

“A lot of people don’t realize that about 70 percent of the ducks that are raised or breed in the Dakotas end up moving into the Mississippi Flyway each fall and winter,” Reynolds said.

Johnson, migratory game bird management supervisor for Game and Fish in Bismarck, said the project will target hens that are just coming out of molt, the time in late summer and early fall when they lose and replace all of their old feathers and temporarily can’t fly.

The birds typically are skinny when they finish molting, Johnson said, and researchers aim to learn whether the hens can adapt to the weight of the transmitters and behave normally.

If they do, he said, the study eventually could expand to a larger midcontinent-wide project involving more birds.

The technology has great potential, Johnson said, but because of the expense, researchers need to fine-tune their objectives before expanding the project.

Johnson serves on a national technical committee that will tackle that challenge

“The downside because of expense is you end up learning a lot of information about a few birds,” Reynolds said. “But with conventional [radiotelemetry] equipment, you learn less with a lot more.”

Both approaches have their place in waterfowl research, he said.


Reynolds said researchers will be watching to see what happens to the GPS-equipped hens after they leave the breeding grounds this fall.

Bottom line, the study has to provide enough information to justify the cost.

“If hunting pressure was high enough, and 70 percent of them got shot before they even migrated, you’d have to question whether it was worthwhile putting so much money into something and getting so little data,” Reynolds said.

If the expense pays off, though, the possibilities are exciting.

“It’s expensive in the initial cost, but when you start to think about how much it would cost, say, to go out and radio 50 hens and follow them for three months and track them on the (breeding) grounds, projects like that have been done for years, and they’re expensive,” the DNR’s Cordts said. “Here you can sit at your computer and get the data. Initially, it’s somewhat scary sticker shock for some people, but for what you’re getting, it’s not.”

And like any technology, what’s out there now will only get better.

“At some point in the not too distant future, that technology is going to really open up the duck information pipeline,” Cordts said. “It will be just amazing what we can actually get.”