Thanks to their distinctive yellow peepers and dark heads, common goldeneyes are one of the easiest ducks to ID as they arrive in cottage country, flying in pairs and flocks, in April and May. They’re insectivores—they love water-dwellers such as caddis fly larvae and dragonfly and mayfly nymphs—and can eat 1,700 bugs in one day.
Goldeneyes are also called “whistlers” because their wings make a whistling sound when the birds fly, especially through cold air. And though both males and females have yellow eyes, they aren’t born this way. Hatchlings begin life with grey-brown eyes, and, after a series of rainbow-like transformations over five months (purple-blue to blue to blue-green), end up with pale greenish-yellow eyes that eventually darken, at least in the case of the male ducks.
Goldeneyes nest for about a month. A hen who can’t find a workable site—a big, empty, abandoned woodpecker hole, say—will sneak her eggs into another cavity-nesting bird’s clutch, and have the mother (often a wood duck or a common merganser) raise these unrelated ducklings with her own brood.