Although we can’t see the owlets yet it is safe to presume that the great horned owl eggs have hatched. On my walk this morning I found the remains of a rabbit that was probably taken by a great horned owl last night, and by now is in the process of speeding the growth of the owlets along. This spring there are both great horned and barred owls nesting in the Greenway.
This is a great time to pick up a few bird calls. There aren’t so many species as to be overwhelming yet, and the birds are quite vocal. There are Apps you can put on your cell phone with all of the calls, or you can just Google them up on your computer. The common species you will hear right now are downy, hairy, pileated and red bellied woodpeckers, northern flickers, white breasted nuthatches, black capped chickadees, cardinals, robins, bluejays, wood ducks and mallards.
One bird that is particularly loud and vocal right now is the northern flicker. The flicker is unusual for a woodpecker in that they migrate south for the winter. The only other Wisconsin woodpeckers that migrate are the red headed woodpecker and the yellow bellied sapsucker.
If you walk the asphalt trail you are pretty much guaranteed to hear and see both wood ducks and mallards. They are actually much easier to identify by call than by sight. The wood duck is called the ‘squealer’ because their call is a very distinctive squealing sound. Back in the 1800s the wood duck was called the summer duck, in fact the Audubon print I have of the wood duck has it labeled as the summer duck. It acquired that name because the bulk of the other species of ducks migrated further north to nest, whereas the wood ducks commonly nested here in the Midwest, as well as further south.
Wood ducks are cavity nesters, meaning that they nest in the cavities of hollow trees. Because they nest in cavities they will readily accept man-made duck houses, the BCPF has put up several, and is adding a few more every year. Other ducks that will nest in duck houses include buffleheads, goldeneyes, and hooded and common mergansers. In northeast Wisconsin the most common after wood ducks to use nesting boxes is the hooded merganser. A friend of mine has a small pond with two duck boxes, and almost every year has wood ducks in one, and hooded mergansers in the other!
Both wood ducks and hooded mergansers practice parasitic nesting, meaning that they will drop eggs in other duck’s houses. A wood duck baby being raised by hooded mergansers or vice-versa has a very confusing early life because their diets and feeding styles are quite different. Wood ducks are called puddle or dabbling ducks because they only duck their head into the water and feed largely on an herbivorous diet, with a few aquatic insects and other invertebrates supplementing their diet. Hooded mergansers are diving ducks, as they dive underwater and feed primarily on a carnivorous diet made up of fish, aquatic insects and other invertebrates.
The best nature show going on right now is not in the Greenway, but can be seen and heard on a property owned by the BCPF outside of the city limits. The snipe are doing their ‘winnowing’ a courtship display done while in flight. While not as famous as the sky dance of the woodcock, immortalized in Aldo Leopold’s Sand County Almanac, the sky winnowing of the snipe is every bit as spectacular. The display of the snipe is called winnowing, because that is precisely the sound made by the birds while in flight. They make the sound with their wings, while doing a slight dip in the air. They also make a distinctive call just before they land back on the ground. When you first go out to watch the snipe you will hear the winnowing, but probably be a little frustrated trying to see them. With patience you will eventually start to pick them out in the sky, and if lucky one might land close to you.