Welcome to Frank's Field Notes, a semi-regular look at what’s happening across the Prairie Pothole Region during spring migration and breeding season.

Part field journal, part migration report, and part window into duck country, Delta Waterfowl Chief Scientist and President Dr. Frank Rohwer offers firsthand observations from the field on ducks, geese, weather, habitat conditions, and the annual return north.

Three Pairs of Teal on the Road - It must be the p...

5/10/2026

Females searching for an upland nesting site like to land in an open spot that has no predators.

Timing of Pair Counts

5/9/2026

We believe the best timing is when there is a 1:1 ratio of paired birds and lone males, which we assume have a hen that is on a nest.

Drying Fast in Bismarck

5/8/2026

When seasonals and temporary ponds hold water into summer the prairies really hold ducks. This year is better than last, but not great.

Prairie Arrival Order Does not Match Nesting Dates

5/7/2026

Check out these timelines of arrival and nesting dates.

Last to Arrive - Different Breeding Strategy

5/6/2026

The typical last duck to get to the prairies arrived at Bismarck about a week ago.

Some Individuals Pair Late

5/4/2026

Unlike most birds, ducks form pair bonds in the winter – many months before nesting.

Redefining Spring

5/3/2026

First hatch was just a few days ago. In my opinion that should be the definition of spring, not daylength.

Black-bellied Whistling Ducks

5/2/2026

Louisiana is set to start a special short season on them in October 2026.

Boxes Increase Parasitism

5/1/2026

Laying parasitic eggs is not a response to nest shortage, but a strategy to increase Darwinian fitness – the number of genes (kids) in the next generation.