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.

Delta Marsh Midges

6/10/2026

Midge larvae are the engine that drives the great productivity of ducks and other birds at the Delta Marsh.

Marked Hen

6/9/2026

You might be able to see the black antenna over her tail. This poor girl lost her nest, so we may soon get location data from a molt migrations site.

Hooded Merganser Parasitism

6/8/2026

Todd got this picture of a Hooded Merganser in Bismarck that had 15 ducklings (2 not in pic) - surely a result of nest parasitism. Another Hoody laid some eggs in this girl’s nest.

Widespread Waterfowl

6/7/2026

Whistling ducks were previously named tree ducks, but Fulvous rarely perch in trees. In the US they often nest in rice fields.

Beautiful Relatives of Our Blue-wings

6/6/2026

Silver teal (Spatula versicolor) are cousins to our blue-winged ducks – Shovelers, Cinnamons and Blue-wings. All in the genus Spatula – clearly named for that Shoveler bill.

Ringed Teal in Argentina

6/5/2026

Ringed Teal are interesting because they nest in tree cavities in the subtropics or they use old stick nests of colonial Monk Parakeets (bottom 2 pictures).

The Mallards - Most Popular Duck - of Argentina

6/4/2026

Rosy-billed Pochards are the iconic duck of much of Argentina and highly sought after - much like Mallards are in North America.

Spring Snow/Ross's Season Closed at the End of May

6/2/2026

Yearling Snow Geese (left bird with some grey feathers) never breed, so there is no rush to get to arctic breeding areas.

Yippee - rain!

5/31/2026

We have been dry, so seeing those clouds to west and rain falling to the east is magic.

Philopatry to Nest Sites

5/31/2026

Female waterfowl show breeding philopatry. That is jargon for homing to the area where they were raised or settled last year.

Cells Phones are Amazing

5/30/2026

While not delicious, mergansers are certainly beautiful and cool ducks.

Fisher Photographs a Hen Moving her Eggs

5/28/2026

This late nesting Canada Goose is billing the eggs in the top photo, then she settles down again.

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.

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