In May of 1972 when Illinois’ first statewide Spring Bird Count was held, 16 parties of Cook County’s best birders spread out over the county and spent an entire day recording all the birds they could find. Among them they managed to discover ten Canada geese.

This figure was not considered particularly low. The bugling cry of the northbound Canada goose has long been regarded as one of the harbingers of spring. The long V’s of migrating geese begin passing over Chicago at the end of February. By May 1972, all but a few stragglers would have reached the breeding grounds on northern lakes.

But things have changed since 1972. This year’s spring count discovered 670 Canada geese in Cook County, and this was a decline from the 808 reported in 1986. Numbers reported went from 10 on that first count to 14 in 1973, down to 7 in 1974, and then suddenly up to 66 in 1975, 154 in 1978, 234 in 1980, 439 in 1983, and 717 in 1985.

The ultimate cause of this population explosion was the rediscovery of the giant Canada goose, a race of this species that had been thought extinct.

Canada geese range over most of North America, occurring from the Atlantic to the Pacific and from the Arctic coast of Canada to Mexico. Like most widespread species, the Canada goose has evolved a number of separate, geographically divided subspecies. Current thinking puts the number of these subspecies at 11.

All of them share the basic color scheme of the Canada goose: black head and neck with white cheek patches meeting under the chin, grayish-brown body. But they differ markedly in some of the details of the plumage and, especially, in size. A typical gander–males are the larger sex–of the cackling goose of Alaska weighs only three to four pounds. A big gander of the giant Canada goose might weigh as much as 24 pounds.

The giant Canada goose once inhabited large parts of the midwest, breeding from the Dakotas to the western Great Lakes. It could be identified by its great size and also by its massive bill and an extension of the cheek patch onto the back of the neck. Some birds also showed a white patch on the forehead.

It was a rather sedentary race. Each autumn, northern birds passed over the midwest on their way to the Gulf Coast, but the giant Canada goose stayed home, moving only as far as was necessary to obtain food.

It was hunted mercilessly year-round, and it lost much of its nesting territory to development. By 1920, it was thought to be extinct.

But then, in 1960, an ornithologist named Harold C. Hansen discovered that a flock of geese wintering near Rochester, Minnesota, actually belonged to this subspecies. The giant Canada goose was back from the dead, and suddenly, everybody wanted some.

Rochester was the first to get them. Birds were transplanted to parks and golf courses and they immediately felt at home there and started to nest.

Fish and game departments from the states within the historic range of the giant Canada goose arranged purchases and swaps with the authorities in Minnesota, and soon breeding populations had returned to lands that had not seen a gosling since World War I.

Geese are famous for their sagacity and alertness in the face of danger. Foraging flocks post sentinels who sound the alarm at the approach of any threat to the safety of the birds, and the birds are quite good at separating the harmless passerby from the approaching peril.

“At the sight of cattle, horses, or animals of the deer kind,” Audubon wrote in 1840, “they are seldom alarmed, but a bear or a cougar is instantly announced. . . . The breaking of a dry stick by a deer is at once distinguished from the same accident occasioned by a man. . . . If a dozen of large turtles drop into the water, making a great noise in their fall . . . the wild goose pays no regard to it; but however faint and distant may be the sound of an Indian’s paddle, that may by accident have struck the side of his canoe, it is at once marked, every individual raises its head and looks intently toward the place from which the noise has proceeded, and in silence all watch the movements of their enemy.”

This ability to detect foes is almost certainly a learned response. Geese are quite long-lived–captive birds have survived past 30 and even wild birds have been known to live for 20 years–so they have ample time to study their world. They mate for life and, unlike almost all other birds, goose families do not break up at the end of the nesting season. Instead, the young birds stay with their parents through the winter and therefore have several more months to absorb the wisdom of their elders.

Obviously, giant Canada goose parents have been teaching their young that the humans in their environment are no threat. Breeding populations established by birds transported from Minnesota have quickly spread beyond the refuges established for them.

In Cook County, they now nest throughout the forest preserves and in city parks, golf courses, cemeteries, and the ornamental ponds that decorate the grounds of corporate headquarters in the suburbs. They have become so numerous that the Illinois Department of Conservation has established a second goose hunting season in hopes of reducing the population.

This season is held in September in order to ensure that the hunters will kill only resident birds rather than migrants. So far, the hunters have not been terribly successful. The birds are feeding in family groups on familiar territory. They are quite regular in their habits. They go to the same places every day, and you can’t attract them with decoys or calls the way you can attract migrating birds.

Another sign of the success of giant Canada geese is that they are now being regarded as pests in some quarters. “Pest” is a word that gets applied to animals as loosely as “weed” is applied to plants. We usually want animals to look picturesque and stay out of our way, and anything that inconveniences anybody in any fashion whatsoever gets called a pest.

Giant Canada geese can be somewhat dangerous, especially to small children. They will protect their nests, if necessary, by assaulting anybody who gets too close. Their wings are their principal defensive weapons, and they are very formidable. Pinions powerful enough to propel a 20-pound bird at 40 miles an hour can bust your arm if they catch you just right.

So if you meet a protective goose in spring or early summer, it is prudent to give ground even if retreating from a bird offends your sense of machismo.

However, the principal charge against the Canada goose is not aggressiveness; it is excessive shitting. Geese are mainly vegetarian. They do eat some insects and earthworms and crustaceans and other helpless animals, but plants are the bulk of their diet.

In the water, they will “tip-up” like mallards and stretch their long necks down to pull up the leaves, stems, and roots of aquatic plants. On land, they eat young green shoots and seeds. They will glean waste grain from harvested cornfields, and in parks and golf courses, they will eat grass.

Their one problem with this diet is that they cannot digest cellulose, the complex starch that makes up most of the substance of green plants.

Cellulose is very hard to digest. Termites do it with the aid of specialized bacteria that live in their guts. Cows do it by chewing the cud and processing their food through a complex system of multiple stomachs. Geese have neither of these devices available, so they must live on the contents of plant cells rather than on the cellulose that forms the cell walls.

Because of this inability to digest their food, geese must eat an enormous amount of stuff to get enough calories to live, and the great majority of the stuff they take in at one end soon comes out the other.

Golfers are particularly offended by this. You drop a nine iron shot three feet from the pin. You think it stopped dead there because you got just the right backspin on it, and then you find out it stopped because it landed in a big pile of goose shit.

The thing to remember at times like this is that the imperfect digestive system of the goose is a powerful argument in favor of evolution. If God created every animal to fit into its place in creation, wouldn’t the goose be able to digest its food?

Evolution assumes that animals adapt to changing environments as well as their genetic endowments allow. Adaptations don’t have to be perfect, they just have to be good enough. If geese can get by with their present gastrointestinal systems, that is all that is required. The golf ball buried in goose droppings discredits Jerry Falwell.