March 30, 2019. This morning Perkins Woods is filled with birdsong. And the Wood Ducks are back! These short-distance migrants have returned from their wintering grounds in the southern United States, probably on the Mississippi River floodplain somewhere south of Kentucky.
By the time we see them, the male has molted out of his fall “eclipse” plumage, which resembles that of the year-round female (also beautiful but in a subtler way), and is sporting his exquisite breeding colors.
James Rennie, writing in 1833 in “The Architecture of Birds,” attempted to describe the male: “The beautiful pendent crest of the summer-duck [an earlier common name] arises from a base of glossy golden green, shading off into a rich violet brown, dashed with interrupted streaks of snow white. The feathers covering the wings are of the same glossy brown, which melts into black, with rich purple reflections of burnished steel; while those on the flanks are delicately fringed and striped with black and white. But …words are not fitted to convey a correct notion of its varying and variegated colours.” And Mr. Rennie gives up, without noting its bright red eye and the bright red on its bill.
It is easy to fall in love with the elegant male. Once when visiting my high school niece, an aspiring veterinarian who was interning at the Boston Science Center, she surprised me with an invitation to behold and actually hold a male Wood Duck. Like Mr. Rennie, I ran out of words to describe the emotion, let alone the colors that put my Crayola crayon box of 64 colors to shame.
Wood Ducks have paired up by January, before they arrive in Perkins. They are visible from the paths, swimming in any of the several vernal pools (springtime ephemeral ponds) in the woods from late March through the end of May. They are often sitting on a downed tree, lined up like proverbial bumps on a log, beautifully reflected in the still water. Or, at first invisible, they may quietly sail out from behind the trees into the open. Or they may be perching in a tree.
If they were preparing to nest, male and female would be investigating a potential nest hole in the trunk of a substantial mature tree, made, perhaps, by the falling away of a tree limb and the resulting rotting heartwood. Although they are cavity nesters, up about 30 feet or higher in trees, their bills are not strong enough to excavate a hole. Then, during egg laying, at the rate of one a day for maybe 10 days, the male would be seen accompanying the female to the nest hole. But when incubation began, the male’s participation would end. After a month of incubation, the eggs would hatch and within a day the female would coax the young to drop down from the tree onto the ground and then lead them to water.
And therein lies a mystery: what are these Wood Ducks doing in Perkins? They have dependably signaled spring for many years, arriving in late March and leaving at the end of May, exactly during nesting season. Yet there are no records of their ever having nested here. Although observers occasionally report what appears to be mating behavior, there are no reports of the nesting behavior described above. The female definitely wouldn’t be hanging around on a log all through April and May, although you could expect to see the male. It can’t be because they are too young: Wood Ducks are ready to breed the first year after hatching. Perhaps the earliest arrivals are on their way to their nesting grounds, some as far north as Alaska or nearby in the Chicago area. Perhaps they are ducks who have nested unsuccessfully elsewhere and need a place to hang out for the rest of the spring until the vernal pools dry up in summer. Perhaps those we see on one day are not the same as those we see on any other day.
Perkins Woods, the smallest Forest Preserve in Cook County, is what is known ecologically as a “flatwoods.” Flatwoods are relatively rare. They occur on flat land of poorly drained clay, on a shallow water table. Vernal pools, created by accumulating snow melt and spring rains, occur in the small depressions and typically, though not always, dry up in mid-June.
Green ash, elm, swamp white oak and basswood trees are well adapted to flatwoods. It is these ephemeral woodland ponds that draw the ducks. Unfortunately for Wood Ducks, however, there is no stream or larger lake nearby. The closest waterway is the North Shore Channel, too far for ducklings to travel safely.
Perkins Woods is known countywide for its gorgeous spring display of native wildflowers, with the best viewing for wildflowers in late April and May.
Perkins’ nesting birds including Black-capped Chickadees, Great-crested Flycatchers, Downy and Hairy Woodpeckers and, in the past, Coopers Hawks.
Whatever the explanation for their presence, the Wood Duck’s beauty adds to the floral display to beckon a visitor to Perkins Woods. The Wood Ducks will be there as long as we have April and May showers to replenish the pools.