By Staff
One of the last things we'd think of as cavity nesting birds is ducks. Ducks belong in water not high up in a tree out in the forest, right? Most of us know wood ducks nest in trees, but they aren't the only quackers that nest in tree cavities. What's surprising about the others is, with just one exception, they're not secretive, forest dwelling ducks like the woodies, they're open water diving ducks that struggle to even walk on dry land.
Two of these tree nesters are the common goldeneye and Barrow's goldeneye. The common goldeneye we often see in these parts during migration to and from their breeding grounds in southern Canada. Their normal interior haunts are lakes and large rivers. Its cousin, the Barrow's goldeneye, is more of a sea duck, breeding along coastal British Columbia and Alaska to the west and the shores of Labrador and Greenland in the east. The tiny bufflehead is another big water diving duck that we often see here in the winter. Come spring, it too, heads for the Canadian provinces in search of a hollow cavity in which to nest.
Rounding out the list of duck tree nesters are the common merganser and hooded merganser. The common merganser winters in these parts but also heads to southern Canada for nesting chores. The gorgeous hooded merganser is much more wood duck-like in its haunts and habits. It even rivals the wood duck in the beauty department. It breeds throughout the U.S. and southern Canada. They frequent the same creeks, forest ponds and secluded marshes that wood ducks do and compete with wood ducks for nesting trees.
Despite the great differences between these species, the nesting and brood raising process is remarkably similar. The preferred height for the nest cavity is 10 to 20 feet high, but 30 or more feet up is okay, too.
In a pinch, cavities just a few feet off the ground are utilized. Ideally, the tree would be very close or even over the water but that is a luxury. Suitable nest cavities are hard to come by and all will set up housekeeping a half-mile or more from water if necessary.
I've seen a number of wood ducks nesting in city trees and house chimneys in downtown Dowagiac over a mile from any water. I can't say how successful the young one's march to water was but that goes to show how difficult it is to fined a decent nest hole. All will nest in properly constructed man made nest boxes. In fact, wood duck nest boxes coming into vogue in the mid 1900s was one of the primary contributors that brought the wood duck back from serious decline. None of the tree nesting ducks constructs a bona fide nest. They just lay the eggs on whatever wood chips and debris naturally occur in the cavity. There's a tip for those of you with wood duck nest boxes – put several inches of cedar chips in the bottom of the box, which also deters ants. During and after the egg laying process, which can take several weeks, the female adds down plucked from her undersides for additional insulation.
Amazingly, all the eggs of the clutch hatch within several hours of each other. The chicks are born precocious, meaning their eyes are open, they're covered with down and they can walk. They only stay in the nest 24 -36 hours before mom coaxes them to take the big step. One by one they bail out of the cavity opening, sometimes plummeting over 30-feet before they crash to the ground. Unbelievably, the chicks are almost never injured. Their bones have not yet developed and their skeletal structure is still mostly pliable cartilage immune to the crash landing. Then comes the perilous march to water where they are at the mercy of all predators from hawks and raccoons to Chevrolets. Once in the water they are self sufficient, paddling around, diving and feeding themselves. Mom watches over them for a while but they are essentially on their own. Now that's a short childhood! Carpe diem.