Nature Lab

By Eleanor C. Hasenbeck | September 1, 2017
From Missouri Conservationist: September 2017

Each month, we highlight research MDC uses to improve fish, forest, and wildlife management.

Waterfowl Management: Tracking Mallard Migration

As the first mallards arrive at Grand Pass Conservation Area in late September, Chris Freeman counts them. A few green heads stick out from the flocks of teal, pintails, and gadwall. This is a zero.

In a few weeks’ time, the mallards will catch an arctic front, and more than 100,000 will find their way to feed at Grand Pass. This is a 10 — peak migration. Freeman, an MDC wildlife management biologist, is part of an international network of waterfowl managers and researchers ranking the mallard migration.

As the birds travel south from their summer breeding grounds, managers report a weekly ranking between 0-10, which measures what stage of the migration the area is in. MDC mapping specialists piece these data points together to create a heat map of the migration, much like a weatherperson creating a temperature map using data from different weather stations.

“To me, tracking migration is one of the unique ways to enjoy nature,” said MDC Waterfowl Biologist Andy Raedeke. “Just knowing that you’re witnessing that movement as it happens, and across state, even national lines — that’s really exciting.”

The information is useful to both hunters and managers. If Freeman knows thousands of ducks are bedding down in parts of South Dakota or Iowa, he also knows the next northerly wind will likely bring thousands of hungry mallards to his area, and he can manage the habitat to make more food accessible. Over the long-term, tracking annual migrations can help researchers notice and understand changes in the pattern and timing of migration.

Monitoring Mallards

Every week from late September to early February, more than 100 experts rank the progress of mallards counted in their areas.

  • 2 Countries involved in data collection: Canada and the United States
  • 170 North American data-collection locations
  • Peak number of mallards counted in Missouri during the 2016 fall migration: 991,796

To view the mallard migration app, visit

This Issue's Staff

Editor - Angie Daly Morfeld

Associate Editor - Bonnie Chasteen

Staff Writer - Larry Archer
Staff Writer - Heather Feeler
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek

Creative Director - Stephanie Thurber

Art Director - Cliff White

Designer - Les Fortenberry
Designer - Marci Porter

Photographer - Noppadol Paothong
Photographer - David Stonner

Circulation - Laura Scheuler