Nature Bulletin No. 650   October 7, 1961
Forest Preserve District of Cook County
John J. Duffy, President
Roberts Mann, Conservation Editor
David H. Thompson, Senior Naturalist

****:WILDLIFE IN CHICAGO

Few people realize that there is enough native wildlife worth 
mentioning in roaring, jam-packed Chicago, nor that very much of it is 
left in its fringe of adjoining suburbs. Surprisingly, this is not the case. 
Just as rural people become accustomed to urban life, some wild birds 
and mammals have adjusted to city life and are holding their own. A 
few kinds seem to be more numerous in parts of metropolitan Chicago 
than they were in those same areas a hundred years ago.

The white-tailed deer, long extinct in this part of Illinois, is on the 
increase in the Chicago region. In recent winters two of them, perhaps 
chased by dogs, were rescued from the ice on the lake front -- one at 
Jackson Park and the other in the Calumet region.

The gray squirrel appears to have greatly increased its numbers over the 
past few decades in the suburban towns and over large portions of the 
city. Winter and summer, in parks and around homes, large numbers of 
people regularly feed them table scraps and nuts for the fun of watching 
their lively frisking. Like other wildlife in cities and towns, they are 
fully protected by law against guns, traps and poison. As if this weren't 
enough, they often gnaw into attics and move in with us.

On mornings after every fresh snowfall the dot-dash tracks of cottontail 
rabbits are seen crisscrossing lawns, city parks and cemeteries. During 
the daytime, even in the closely built, heavily populated sections of the 
city they squat motionless in their grass-covered nests or "forms". The 
females scoop out cup-shaped hollows and line them with their own fur 
for hiding their newborn young.

The opossum, a typical woodland fur-bearer, has become common in 
towns and, in recent years, is invading deeper and deeper into the heart 
of Chicago. Dim-witted and slow with a top speed no faster than a brisk 
waddle, this strange nocturnal mammal seems to survive in cities 
because it is an omnivorous scavenger and because they reproduce 
rapidly. More than once, newspapers have reported possums in the 
Loop.

Among the kinds of songbirds nesting in the city 'he most common and 
widespread are the grackle, robin, cardinal and wood pewee. The night 
hawks or bullbats, seen catching insects on the wing as they zigzag over 
the city at dawn and dusk, lay their eggs on the flat roofs of tall 
buildings without any nest whatever.

By far the greatest number of wildlife species seen in Chicago is found 
among the migrating hordes of birds that, both spring and fall, follow an 
ancient migration route along this west shore of Lake Michigan. For 
example, many kinds of tiny warblers pass through Chicago, even 
through the Loop, as if the city were not a hazard. On their way 
southward, purple martins gather by the thousands to feed and rest at 
Montrose Harbor and near the Shedd Aquarium. Flocks of Canada 
geese, perhaps confused by the city's lights on nights with low-hanging 
clouds, often circle for hours and waken thousands with their honking. 
The gulls which throng our harbors are reared on several islands in 
northern Lake Michigan. Several species of diving ducks spend the 
winter in the open waters of the lake. Occasionally, in winter, a few 
snowy owls from the distant Arctic were seen hunting rats in waste 
places and the city dumps. Also a migrating bald eagle stopped over for 
a few days at Belmont Harbor to feed on dead fish.

The richest wildlife populations within Chicago's city limits are at Lake 
Calumet, Wolf Lake and along the Little Calumet River. On their mud 
flats are to be found all of the kinds of shore birds in this entire region. 

Large cattail marshes are dotted with muskrat houses and, in summer, 
are filled with the clamor of nesting red-winged blackbirds.