NORTHERN CALIFORNIA – It’s hard to believe that the pretty little wood ducks (Aix sponsa) were brought to the brink of extinction in the late 1800s.
Deforestation, wetland loss and hunting of the birds for meat production were the main culprits, but like the egrets of the same time, wood duck feathers were also prized for ladies’ hats.
Conservation efforts including the U.S. Migratory Bird Treaty Act (1918) preserved the species. Even though they are still hunted (with a limited take of two birds in California) their numbers are currently on rise thanks to continued protection and the establishment of human-made nesting boxes.
At only about three-quarters of the size of a common mallard, the male wood ducks are distinctly patterned with an iridescent green head (decorated with white lines and curves), a glossy chestnut colored chest and buff sides.
Although the females’ coloring isn’t as striking, they still cut a lovely gray-brown figure with their speckled breasts, and their white rimmed eyes with yellow eyeliner.
Besides their coloring, what makes these ducks unique is that they have no close ancestral relatives other than the brightly colored Mandarin ducks.
Unlike most other ducks, too, wood ducks have some special adaptations that make them able to climb, perch, nest and freely fly around trees.
Their somewhat stocky body and short broad wings make them very maneuverable in flight, and their feet are equipped with claws that allow the ducks to climb trees and perch on branches.
Even the newly hatched ducklings have use for their claws. When they are just one day old, they leap from the nest onto the ground (which may be up to 50 feet below), using their claws and tail to brace themselves just before the jump.
Unless they land on something especially hard, the long fall doesn’t injure the ducklings. Their tiny bodies are so light that they literally just bounce when they hit ground.
Wood ducks prefer to nest in tree cavities but since they are unable to excavate cavities on their own and have to rely on natural openings in trees, they have also adapted well to using nest boxes. (Northern Flicker nesting cavities are sometimes used, but that is something of a rarity.)
Usually, the nest which is lined with feathers and little else is between 10 and 50 feet off the ground somewhere near a water source, like a lake, wetlands area or even an urban pond.
Females may lay eggs in several different nests before they pick one to brood in, so it’s not unusual for there to be a broad mix of eggs in each nest.
Some nests, called “dump nests,” don’t live up to the females’ instinctive standards and the eggs in them never get incubated at all.
Normally, the females will lay between six and fifteen eggs. But in areas where the nests are close together and the females are all laying in one another’s nests around the same time, there can be up to 30 or 40 eggs in one nest.
Although such broods can be large, most of the ducklings don’t make it to maturity. Their tiny “snack” size make them easy prey to a wide variety of predators including other birds, snakes, and predatory fish like Northern Pike.
About 80 percent of a wood duck’s diet is made up of the seeds of aquatic plants, but the ducks will supplement that diet with insects, snails, berries, acorns and other plant matter like water primrose, duckweed and smartweed.
Ducklings eat the same diet as their parents, and although their mom may stay with them for about six weeks after they hatch to protect them and help them find things to eat, she will generally leave the ducklings to their own devices by the time they fledge.
If you would like to try your hand at building a wood duck box keep in mind that the kind of habitat available around the box is as important as the construction of the box itself.
The ducks need foraging sources and access to water. Building nest boxes, though, allows you to help preserve the species and affords you some insights into their unique behavior.
Mary K. Hanson is a Certified California Naturalist, author and nature photographer. She will be co-teaching a naturalist course for the public through Tuleyome in early 2018. Tuleyome is a501(c)(3) nonprofit conservation organization based in Woodland, CA. For more information visit www.tuleyome.org .