Banding Waterfowl in South Dakota
by Phil Thorpe
To play off a Beatles classic…and due to circumstances beyond our control, banding in 2021 once again finds us…“Back in the U.S., back in the U.S., back in the U.S.A.”
While I missed orchestrating and coordinating the annual U.S. — Canada cooperative waterfowl banding operation in Saskatchewan. I’ve enjoyed banding in the U.S. and exploring different areas of waterfowl habitat the last two years. This year, I spent 3 weeks in South Dakota with fellow U.S. Fish and Wildlife Service Pilot Biologist Terry Liddick (crew leader) and U.S. Fish and Wildlife Service Refuge Manager Miguel Jimenez. Last year, this banding station caught over 1,200 mallards so I was excited at the prospect of filling our target species quota, as well as the potential of banding some wood ducks, generally a novelty for us.
I’ve banded a lot of ducks in my 27 years working in the prairie pothole region — but only four have been wood ducks, and all of those were in Saskatchewan! Wood ducks are an interesting species, with their red eyes, exotic plumage, agile flight, and novel nesting behavior in tree cavities. Nesting holes are typically in living trees and over water, where the ducklings land when they jump out of the nest hole (watch out for that first step!). When I think of wood duck habitat, the flooded timber of Louisiana or Arkansas come to mind…South Dakota does not. But apparently wood ducks also like South Dakota — and judging by the traps full of woodies we caught every day, they must like it a lot! Terry banded a personal record of 164 wood ducks in 2020, but this year our station banded almost 3 times that!
Wood ducks were near extinction by the early 1900s, but thanks to the Migratory Bird Treaty Act and careful management, their population now numbers about 3 million birds. Why South Dakota then? Our other banding crews in eastern South Dakota and North Dakota also banded hundreds of wood ducks — but where are all these wood ducks coming from? They prefer cavities excavated by pileated woodpeckers, which like old growth trees, but trees (old and young) are actually lacking in the Dakotas. There is a vast amount of wood duck literature out there, but in a brief review I found no peer reviewed papers on prairie wood ducks other than that birds are expanding their range along river corridors in Nebraska and the eastern Dakotas. Their presence piqued my curiosity and that of my colleagues.
Most of the wood ducks we caught were adult males (AHY-M in banding lingo). Many species of ducks have molt migrations consisting mostly of adult males because males leave the breeding grounds and fly off together in flocks as they molt their wing and old breeding plumage feathers. We think this is what our South Dakota wood ducks may have been doing. Where they were coming from is the real mystery though — some molt migrations can be hundreds of miles away from their breeding areas, so maybe they were coming from the east from the populations along the Missouri or Mississippi or from eastern Nebraska or Kansas? More research is needed to find the answer to the question.
Bands reported from hunters will help answer the question of where these birds spend their time in the late fall and winter, but where they spend the breeding season with their mate may involve tracking males with radio transmitters.
After so many years of banding ducks one might think it could get monotonous. But every year brings something new, like traps full of ducks that nest in trees and stir up curiosity in this veteran wildlife biologist. These discoveries are why I love biology and the questions that drive the science behind wildlife management.
While our crews pined to be back in Canada this year, I think many of us found a curious duck filling our traps and sparking wonder about why they were in the prairies “back in the USA…”