Winter 1999

[TEXT ARCHIVE WEB-PUBLISHED MARCH 2002.
ORIGINAL PRINT PUBLICATION DATE: WINTER 1999.]

Here's what's debuting this season
on nature's stage in Chicago Wilderness

By Jack MacRae

Winter Into Early Spring

Great Fecundity
A warm blanket of snow sounds oxymoronic. But to the meadow voles in my backyard, a six-inch layer of snow is cause for a terrific increase in comfort level. Not only does the air temperature rarely fall below 30°F under the snow, the white covering allows direct, yet concealed, passage from my lilacs to the compost heap. Voles are warmer and safer under the snow than on the bare ground. Two species of voles are found in the Chicago Wilderness, the meadow vole and the superficially similar but more rare prairie vole. Both are known for their amazing fecundity and reproductive abilities.

Voles breed throughout the year, with litters of up to eight young born every six to eight weeks. The young females are sexually mature at the age of one month. Explosive, cyclical population booms may raise the vole density to over 400 individuals per acre every few years, thus making them an important source of energy in a grassland food web. Thank goodness for predators. Meadow voles are found almost anywhere there is long grass. You can locate their intricate maze of runways by parting the thick grass in a vacant lot.

Feeding Wild Animals
I know some people who think if you start feeding birds in the winter, you had better continue or the birds will starve. Not necessarily true. During most winters, the survival rate of birds does not drop when feeders are neglected. The feeding stations generously provided by humans are usually used only to supplement a bird's diet. A study in Wisconsin found that chickadees obtain only 20-25 percent of their daily energy requirement from a feeder, picking up the rest from their foraging trips through the woods and fields. Feeders DO help birds survive when temperatures dip below 0°F, when the energy requirements for our feathered friends increase by 50 percent over their normal winter intake.

Animal Holiday
There are plenty of similarities between groundhogs and badgers. They both live in holes in the ground. They're roughly the same size and shape. Groundhogs have a holiday named in their honor; badgers are the mascot for the premier party school in the country. But that's where the similarities end. Their behavior, habits, and habitats are entirely different. Groundhogs abound in our area. Originally an animal of savannas and forest edges, they have adjusted well to life to in our parks, yards and roadsides. Their food of choice (emerging grasses, flowers, bok choy from my garden) is found everywhere. Groundhogs — like most members of the squirrel family — are active during daylight hours.

Badgers are rare in our area, though they turn up regularly. Originally an animal of sand prairies, they have been unable to adapt to the innumerable changes in the Chicago Wilderness landscape. Badgers are excellent hunters, preying extensively on mice, voles, groundhogs, ground squirrels, and rabbits. They are basically nocturnal. Due to the progressive restoration and management practices in our area's prairies, the future for our badger populations may be promising. The Braidwood Dunes and Savanna in Will County provides many acres of suitable habitat, as does the Midewin National Tallgrass Prairie.

Woodpeckers
Winter is a great time to observe our resident woodpeckers. They are colorful and conspicuous as they dash among the trees. They're also loud. This is the time of year when woodpeckers drum, where they bang their heads against trees to attract a mate and announce their territory. I had a roommate at Southern Illinois University who did the same thing. There are several different species of woodpeckers found within Chicago Wilderness habitats. The elegant looking red-headed woodpecker is found in our open oak woodlands. Pilcher Park in Joliet is a terrific place to spot red-heads as well as the closely related red-bellied woodpecker.

The pileated woodpecker — the largest of our local woodpeckers — is uncommon in our region. They require large tracts of timber. There are a few pileateds that reside in Warren Woods in Indiana, and one used to live along Hickory Creek in Will County, but has not been seen for several years. Hairy woodpeckers, and the similar in appearance (but smaller) downy woodpecker, also live in our forest preserves and older neighborhoods. They can be attracted to feeding stations with suet feeders.

Downtown Foxes
Fox couples throughout suburbia are currently busy checking out real estate. They will use several shelters during the course of the spring as they move their family frequently. Their ideal home is under the root of an overturned tree, but they're not too choosey. A pile of concrete rubble will be suitable. They'll den almost anywhere, especially when the local vole population is booming. In downtown Naperville, a couple of blocks from the Cock Robin Restaurant, lives a red fox. The neighbors see her scamper through the backyards and across the school playground. You can track her through the snow by following her straight line of foot prints. She used to live in a small tangled plot of box elder, until it was recently cut down for the new River Walk expansion.

Wood Ducks
I'd like to propose a toast to Mr. A.C. White of Connecticut. In the early years of this century, it was feared wood ducks had become extinct in the wild. Their habitat had been devastated through development and forestry practices, and they were a favorite target of market hunters. In 1914 there were certainly fewer wood ducks in the wild than in captivity. Mr. White came to the rescue. He set up a captive, breeding colony of wood ducks and, for 17 consecutive years, raised and released thousands of ducks into the wilds of North America. Thanks A.C.

Many wood ducks return to the Chicago Wilderness to nest in the early spring. All along the Des Plaines River and its tributaries you can find these beautiful birds, who exhibit their most colorful plumage at this time of year. In the early morning hours at Fullersburg Woods in DuPage County, there's a pair of wood ducks who sit on a low branch of an oak, watching me prepare the kettle of maple sap for boiling over a fire.

Tora! Tora! Tora! I don't want to sound overly macho or uncaring, but for those of us who like our nature "red in fang and tooth", the sight of a cooper's hawk attacking a bird feeder is a beautiful thing. Swooping in with a low approach, this medium-sized bird of prey slams into its victim feet first, sending an explosion of feathers into the air. Way cool! Cooper's Hawks, and the closely related sharp-shinned hawk, specialize in a diet of song birds. With long tails and rather stubby wings, these accipiters are designed for maneuverability and quick aerial movements.

Both birds favor open woodlands for nesting sites and have benefitted from the removal of buckthorn from our natural areas. A true success story is that Cooper's hawks have so increased in population that they have been removed from the endangered list in Illinois. Way to go! The Old School Grove in Lake County, Illinois, with its stands of mature oaks along the Des Plaines River, provides perfect habitat for these feathered hunters.