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.

Yesterday's Milestone - First Marked Canvasback of...

5/27/2026

This hen is a couple of days from being the first hen of close to 170 nesting Cans to hatch her clutch.

Robins Clean; Ducks Mostly Don't

5/27/2026

This hatched Robin egg (about ½ inch in width) was in my yard today. It reminded me that most birds take egg shells and other trash away from their nest.

Status is Iffy

5/25/2026

The standard protocol for decades: if fewer than 5 males of same species in a group, then count each male as paired.

The Marsh Master Makes Burning Feasible

5/24/2026

Burning is a good way to open the area so pairs can settle.

Territorial About the Water and its Resources

5/24/2026

Most dabblers are highly territorial about the water where momma feeds. Not territorial about nest sites.

Dr. Fowler (left); Dr. Nyman (center) and graduate student Braden Bodin.

Moist Soil Team at Delta Marsh

5/22/2026

We had several productive days at Delta Marsh. The reigning hypothesis for our low plant diversity in moist soil: SALT.

Todd Arnold got the First Mallard Brood Picture in...

5/21/2026

Early hatch is always good, especially in a fairly dry years like this one in Bismarck area.

Amalgamated Brood

5/18/2026

Giant Canada Geese are normally solitary nesters, but parks in cities (like Winnipeg) get semi-colonial nesting.

Biparental Care

5/17/2026

Males and females have split roles. If danger approaches mom slinks away with goslings.

Ducks and Oil - They Mix

5/16/2026

A few years ago we worked in the Bakken to test whether ducks avoided oil extraction.

ND has Lots of Wind

5/15/2026

North Dakota is blessed with wind, coal, gas and oil, but only one is labeled green energy.

Too many big beautiful birds?

5/14/2026

Occasionally wildlife management is too successful. Too many deer negatively affect forest regeneration and cause highway fatalities.

Trumpeters in Minnesota

5/13/2026

In the 1930’s we thought only about 40 Trumpeters still existed - hidden in the Red Rocks Lakes area of Montana; extinction seemed eminent.

Swan Identification

5/12/2026

How to tell a Trumpeter Swan from a Tundra Swan

Ruddy Duck Video

5/11/2026

This video shows the most frequent display by male ruddies to impress females.

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.

First Can Nest at Minnedosa

5/5/2026

First nests for Cans are typically started in early May, but thaw was late this year in parkland Canada.

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.

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