Insects: fueling the next generation of ducks

By Ducks Unlimited Canada

By Ducks Unlimited Canada | April 8, 2016

There is a whole world under the water surface which most people never know exists.

A world of larval, nymph and adult invertebrates uniquely adapted to the water they live in. And when it comes to migrating waterfowl, the role of insects is crucial.

invertebrates2Eiders, scoters and mergansers eat mostly invertebrates and other animals, such as fish, year-round. For most other female waterfowl, invertebrates are especially important in the spring, after they have migrated back to their breeding grounds and begin laying their eggs.

For a female mallard, laying a nest of nine eggs is equivalent to a woman having nine eight-pound babies. The bigger challenge is that she will only have about nine days to do it. She will need to draw on the fat reserves she has stored from eating plants and grains all winter. She will also require a significant amount of protein and calcium that can come only from the aquatic invertebrates she will find in the wetlands she returns to in the spring.

broodThe diet for a female blue-winged teal will go from mostly plants in the fall and winter to almost 95 per cent invertebrates each spring. Ruddy duck diets will be close to 100 per cent invertebrates. Even a wigeon, whose bill is more like a goose’s and adapted for grazing, will switch its diet to 40 per cent invertebrate foods each spring. The ducklings, like their moms, will also depend exclusively on bugs for the first few weeks of their lives. With not much fat on their bones, newly hatched ducklings will require the protein offered by bugs for muscle, feather development, and the energy to grow.

The challenges of annual cycles, and the changes that have occurred in our waterways as the results of land development over the last 150 years have affected a large number of Canada’s wetlands. The success of invertebrates and the breeding waterfowl they support rely heavily on healthy, intact habitat.

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