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.

Being an adult male is good

9/9/2026

We found a great pea field that held about 5,000 Mallards and Pintails.

OOPS - small but not a teal

9/8/2026

Mistakes happen – that is a hen Bufflehead, not a Blue-winged teal.

Bill Spots for Aging Female Ducks

9/7/2026

Another way to age some female dabblers is by the size of the bill spots.

Peas - cocaine for ducks

9/6/2026

Mallards and Pintails are addicted to field peas.

Distinguishing age classes

9/5/2026

An easy way to split age groups is by looking at tail feathers

Teal season opening soon - differentiating sexes

9/4/2026

Special teal season start soon in many states. All blue-wings are in basic (aka eclipse) plumage at this time of year.

Christmas in September

9/3/2026

Spent September 1 (Christmas) in Saskatchewan with Spaniel Spat – glorious.

Bpop report out - not all bad news

9/2/2026

Cans and Scaup were both up 13% over last year.

Fun banding video

9/1/2026

Charlee spliced together a one-minute video of Delta banding.

Delta Marsh banding

8/31/2026

Species totals for Banding effort.

Nice sunset - fall is coming

8/30/2026

That isn’t the Missouri River, but we had a great sunset with much smaller flocks of resident Canada Geese.

Very late brood

8/29/2026

Today I made an excursion up to southern Manitoba and southeastern Saskatchewan.

Plunge Dive Foraging

8/28/2026

We have both Common Terns and Forester’s Terns at Delta Marsh. They both plunge dive to catch small fish.

Bufflehead, Lesser Scaup, Ring necked duck

British Columbia Breeding Population Numbers

8/27/2026

I just got a copy of the spring Breeding population survey for BC.

Banders at Delta

8/26/2026

The Delta banding crew is mostly comprised of southern graduate students that are up north getting prairie and banding experience.

Delta Banding going well

8/25/2026

Our banding crew at the Delta Marsh has well over 1,800 birds banded this month.

Fantastic flight in a Beaver

8/24/2026

I had a terrific flight in a 1950’s era de Havilland Beaver a couple hours out the Alaska Peninsula from King Salmon.

Tundra swans in abundance

8/23/2026

Tundra Swans are abundant here on the Alaska Peninsula.

Tree Swallows at Delta Marsh

8/22/2026

Thousands of Tree Swallows come to Delta in the late summer to molt where there are millions of midges.

Those wings are expensive

8/21/2026

Growing feathers requires substantial amounts of proteins with scarce amino acids.

Not long on the wing

8/20/2026

This young female Shoveler has probably been on the wing for less than three weeks.

Different migration schedules for the sexes

8/18/2026

Male ducks don’t do much parental care, so they molt earlier than females and are ready to migrate south earlier than females.

Several large broods at the MERP cells

8/18/2026

Some broods look like they lost no ducklings from the time of hatch.

Error yesterday - 15 bird bag limit

8/17/2026

Special seasons designed to reduce populations typically have liberal limits.

Opening morning

8/16/2026

Canada Geese were shot out of North Dakota, but rapid recovery started in the 1990’s.

Another great figure by Todd Arnold

8/15/2026

Blue-winged teal have a “faster” life cycle than Pintails or Mallards.

More great stuff from Delta Science Forum

8/14/2026

Reproduction drives duck numbers FAR more than survival or other factors.

Molt status matters - at least we think it does

8/12/2026

The photo shows the three options for wing molt

Delta Science Forum - cool new results

8/11/2026

Day 1 of the Delta Science Forum is in the bag.

The food for half the birds at Delta Marsh

8/10/2026

Males fly in huge groups that the girls briefly join, get a boy, mate, and lay eggs.

California breeding ducks down

8/6/2026

California Game and Fish released their statewide spring breeding duck count this week.