Over the long haul of time, the growth of cities has taken an enormous toll of wildlife habitats and affected those remaining in a number of ways. First, the construction of the city has completely destroyed many habitats and has modified others. The former is particularly true where wetlands have been filled. Second, the construction of cities has altered or destroyed migratory routes. In a few cases, modification has been a wildlife boon—such as properly planted cities where large numbers of street trees have proliferated the "edge effect" of the forest and thus provided more habitat for birds than a natural forest in the same area.

The natural components of the city, however, form a new ecosystem that can contain some but not all of the animals previously present. In considering wildlife and the city we must ask whether there are habitat connections with the hinterland, the stream valley, the greenbelt, the river, the watershed, or the lake that remain undeveloped. Are there pockets of natural vegetation in the form of parks? Are there trees along the streets? Are the yards and gardens of the city dwellers suitable habitat for much of the natural wildlife that we find pleasing? Are there food plants?

Probably food plants are the single most important factor in attracting wild birds to the city. Our penchant for neatness severely limits the growth of food trees, particularly wild black cherries and other seed plants that most attract birds. By eliminating kitchen gardens and replacing them with shade trees and turf, we have further inhibited urban Wildlife.

Yet the feeding of birds in many cities is big business. Most hardware stores sell wild bird wed mixtures and suet seed cakes, as well as bird feeders, bird houses, and an array of apparatus and paraphernalia for feeding and housing birds.

In most cities, the larger and more dangerous animals have been eliminated or destroyed and the rest have fitted themselves into the niches that remain. The animal wildlife, like the plant life, can be a bioassay for the quality of life, and this aspect of wildlife in the city is perhaps as important as any other. Songbirds, squirrels, game fish in the streams, racoon, mink and beaver, all are indicators of a quality environment. Rats and vermin, houseflies, cockroaches, and similar insects are indices showing that the environment is in poor condition. Wild bird populations that are limited to starlings and sparrows indicate over—simplification, a down—grading of the environment.

Since humane control the city ecosystem, they can and should regulate wildlife. When they abdicate this responsibility, the quality of all life suffers. Cats and dogs have become feral and in many instances must now be considered a part of the wildlife in urban predator/prey relationships. In suburban areas where dogs are kept for companionship or for protection, many are permitted to run loose. Children and adults are in danger of being attacked by the packs that inevitably form under these circumstances. Feral dog packs have been reported in such diverse locations as Montgomery County, Maryland, Beverly Shores in the Indiana Dunes, and in numerous Southern towns. In one of the latter, a poll taken among school children showed that their greatest fear was attack by a dog pack. It is possible that coyotes, foxes, and wolves regulate house cats and in some instances dogs too. Authenticated records testify to red foxes preying upon cats, and it is now a common sight to see coyotes in the suburbs of Los Angeles where not a few pets become their prey.

The answer to control of wildlife in the city, as in all wildlife programs, lies in habitat management. If a city is to accommodate wildlife, it must not only accommodate the physical presence of the animal but also provide a home range for it. Large ungulates and large carnivores, in addition to being potentially dangerous to man, require more space for adequate home ranges than a city is able to provide.

In addition, there is the need of migratory animals for continuity of habitat. Whether they are moving north and south or migrating from winter to summer feeding ranges, such animals cannot make their necessary journeys without the life support systems provided by a dependable string of habitats along their ways. Moreover, the biological quality of the habitat and protection from predation by man is important. Migratory animals must have adequate cover, abundant food and if the animal is shy of man, there must be easy escape from man and his activities.

The chemical quality of the habitat is another consideration. This centers around the quality of two essential elements—air and water. Water and air pollution have the effect on natural ecosystems of "simplifying" them by eliminating some of the components. The result of a system thus made poorer is to lower the efficiency of energy use; fewer ecological niches, fewer resident life forms, a less diverse and less energetic system.

Man is not a good "bioassay" for air and water quality. All the plants of the city and fish in the streams could die from lowered chemical quality of the habitat before men would consider himself seriously damaged by the quality of the air and water. There Is ample evidence—in places like Mexico City, Tokyo, and Los Angeles, to name three—that the pollution of air and water severely stresses the vegetation. Yet man continues to live in these areas, apparently only slightly inconvenienced by the enormous pollution.

City dwellers take their water supplies from rivers that are incapable of nourishing anything but trash fish. A recent study of the Potomac River showed that while the water is unlikely to be lethal to humans, a great number of chemical pollutants are present in concentrations just low enough not to constitute a direct threat to man. The Potomac pollutants are not the kinds of materials that are removed by water treatment prior to consumption by man.