Track the Migration by Satellite and Computer
Dr. Andrew Raedeke is a waterfowl biologist at the Missouri Department of Conservation's Resource Science Center in Columbia. In 2008 he helped set up a duck tracking system called the Mallard Migration Observation Network. Its main purpose was to answer the question that has been asked by waterfowlers for generations: where are the ducks?
"In the mid-2000s, many hunters and wildlife professionals were wondering if migration patterns were changing and why some traditional wintering grounds were attracting fewer ducks than they used to. The Arkansas
Game and Fish Commission had launched a satellite tracking study of mallards fitted with transmitters to follow their movements. We expanded this study to learn if these transmitter-fitted ducks were behaving like normal ducks (those without transmitters) and providing locational information that was reflective of the mallard population as a whole," Raedeke explains.
"We fitted 80 mallards with GPS transmitters and followed their movements. We also set up the Mallard Migration Observation Network to compare readings from our satellite mallards with actual in-the-field counts. We did this to test the accuracy of the satellite duck readings and to provide a better idea of where the ducks actually were."
The Mallard Migration Observation Network consists of 125 trained observers who conduct duck counts at locations throughout the Mississippi and Central flyways
. "We asked each observer to provide us with a weekly numerical ranking for the status of the mallard migration at their site," Raedeke continues. "Then, using these rankings, we developed a migration map
to show where mallards are concentrated and how the migration is progressing. We post this map on our Missouri Department of Conservation website (mdc.mo.gov
) for the public to view, and update it weekly."
Raedeke says researchers have learned several things by comparing the satellite duck readings to data compiled through the Mallard Migration Observation Network. "One thing we have learned is that initially, ducks wearing transmitters were behaving differently than birds in the general population. Their movements weren't reflective of what was really happening in the wild. From this, we learned that when you put the transmitters on the birds is very important. Birds trapped in late winter or spring migrated more on par with the general population. Now we can take GPS readings from our transmitter ducks and plot their locations with fairly high confidence that their locations are reflective of the progress of the mallard migration," he says.
What applications can hunters make from this study? "Well, they can visit our website, view the map, and know if the peak of the mallard migration is still to the north of their hunting area or if it has passed them by. If the majority of the birds are still to the north and a good cold front blows through, hunters would probably have more success hunting bigger water where migrating ducks are more likely to show up first. But after the peak of the migration has passed, hunters may be better off hunting smaller, more secluded waters where hunter-wary ‘local' ducks hang out," he advises.
Raedeke adds that the migration map can help hunters decide when to flood habitat on hunting clubs and leases. "In the old days, hunters used to flood all their property before opening day. But now we know that it's better to progressively flood new food and habitat as the season wears on. So hunters can use the Mallard Migration Observation Network map to decide whether to flood or hold off peak flooding a little longer. Then, when the migration gets close to their hunting area, they can provide new water and fresh food at the most opportune time to attract the most ducks," he says.