These familiar ducks showed up here in a small flock of maybe 15 birds in early November. I say maybe 15 because they are diving ducks and some of them were under water at any given moment. A big grebe, probably a Western (Aechmophorus occidentalis) kept them company. I saw a solo ruddy on the North Basin on October 16, and a flock of just five birds on October 22. These ducks migrate in small groups, flying at night.
Ruddies are lucky in that hunters generally leave them alone. When disturbed, ruddies generally paddle away or dive, instead of taking to the air like most other ducks. Shooting ducks on the water isn’t considered sporting, though why killing them in the air is considered a sport escapes me.
Most of these ducks do their breeding in the Prairie Pothole region stretching from Manitoba south through the Dakotas. They build rough nests in vegetation over water. The females lay the largest eggs relative to body size of any waterfowl. A typical brood size is seven eggs. Those add up to 96 percent of the mother’s body weight.
Males tend to migrate to the breeding habitat earlier than females. When the females arrive, the males engage in elaborate courtship rituals, and pairs form. The pairs may not be exclusive, and the females’ consent is not always given. Once paired, the male aggressively defends the female against other males and defends the pair against all kinds of intruders of whatever species. But once the female begins laying, the male usually loses interest and leaves. The female does all the incubating. The chicks can leave the nest and dive for food within 24 hours of hatching. They feed themselves. The female leaves the brood about three weeks after hatching, a month or so before the ducklings can fly. They don’t really need her.
Ruddies have among the largest webbed feet relative to body size of any duck. Their feet are set so far back on the body that they can barely walk. They’re the worst walkers of any North American waterfowl. They may have to push themselves along, sliding on their bellies. In exchange, they’re powerful swimmers and divers. Like harbor seals, they exhale before they dive. They can stay under for 20 seconds, but typically come back up in shorter intervals.
Ruddy Ducks are primarily carnivorous. Something like 75 to 90 percent of their diet consists of aquatic insect larvae and similar invertebrate protein.
At this time of year they are finished breeding and molting, and we see them in their basic (non-breeding) plumage. They’re probably just visiting here, having a bit of a rest stop on their way further south. Usually we’ll see them again in the Spring, and if we see them in May or June we will probably see the males in their colorful breeding plumage, featuring a sky-blue bill, as in this photo I took on the North Basin in May 2017.
Ruddies often carry their stiff tailfeathers raised high out of the water. When they do that here, identifying them is a no-brainer. But they may also keep their tail feathers down. What goes into that decision is one of the many items in the MATWOB file (Mysterious Are The Ways of Birds). Here, for example, is a trio of Ruddies where one carries her tailfeathers up another one carries them level with the water, and the third carries them down.
Burrowing Owl Update
This morning I was unable to see the Burrowing Owl in either of its usual perches, or anywhere else. Time will tell whether it’s just taken a day off or whether it’s flown elsewhere, maybe to a warmer climate. I will report here daily. If you see the owl, please call or text 510-717-2414. Thanks.