INTERSTATE HIGHWAYS with multiflora rose shrubbery planted in their median strips as car barriers have lured southern mockinghbirds as far north as Maine. The birds feed on the rose pips throughout the coldest winters.
Coyotes from the West have spread across the breadth of the country into the Appalachian Mountains. They are "in residence," authorities say, in such cities as Chicago, Cincinnati and Albany, N.Y.
Alligators, although an "endangered species" whose killing is stricly limited, have attacked dogs and children in Florida and Louisiana. They have stopped street traffic, and have turned up on front lawns, even in homes.
There was a time, not too long ago, when wildlife experts feared that creatures like the mockingbird - if not the coyote and alligator - were being driven farther and farther from American cities as each new load of concrete and lumber further expanded municipal boundaries. Soon, it was feared, urban Americans, who make up 70 percent of the population, would see wildlife only on their television sets - and then maybe only in animated cartoons.
But the trend has not been that way. On the contrary, more and more wildlife is showing up in U.S. cities. Experts say some of the reasons are:
A warming climate. Among other things, this has caused the northward "explosive" migration of the Virginian oposum, a grizzled marsupial that uses its hairless tail as an extra arm or leg.
A lack of natural predators in urban settings - which has contributed to another exploding population species, the raccoon. Equally at home in old trees and new chimneys, feeding from tipped garbage cans at night, the racoon persists despite threats from such enemies as cars, youths with air rifles and an occasional brave dog.
Anti-pollution drives. In Washington, an extensive cleanup of the Potomac River has returned beavers to the waterway, even in the vicinity of the capital. Building New Habitats
BUT MOST IMPORTANT is the amazing tolerance and adaptability of many kinds of creatures to man and his urban civilization. Despite his constructions, and sometimes thanks to them, more animals than expected ar surviving in urban environs, both silent and raucous, benign and harmful, intriguing and plain nuisances.
A peregrine falcon has established its scrape, or nest, on a downtown Baltimore bank building. She is the latest of her kind attracted to a skyscrapper aerie by the fast-food promises in plump, slow pigeons. Falcons have also been found living in Chicago, New York, Boston, Philadelphia and Harrisburg.
Sloppy carpentry in new housing developments in Maryland that left unboxed eaves and unscreened louvers has created nesting spaces that now attract hordes of starlings and house sparrows. One wildlife researcher is said to be able to identify the builder of tracts in the new town of Columbia according to the number of birds living in the crevices.
Storm drains, railroad banks and other conduits have made it relatively easy for wildlife to enter cities from rural regions. Interstate highways also permit easy migration from region to region.
The mockingbird moved throughout the Northeast in just eight years, according to Richard M. De Graaf, an Agriculture Department wildlife research biologist. While the rose shrub was responsible in that case, other animals are moving under cover of crown vetch, a flowering plant used to minimize erosion on highways' steep sides.
The energy crisis of the past five years has also affected the wildlife population and its movement into new locales.
Rising gasoline costs have forced highway maintenance crews to reduce mowings along federal and state roads, permitting higher grass and brush cover for wildlife, according to Thomas M. Franklin of the Urban Wildlife Research Center.
Thus, ring-necked pheasants and voles, a dumpy looking field mouse, have proliferated and moved into the Northeast and the Midwest, he said. The voles, in turn, attract perdatory birds. What is more, motorists in these areas say they increasingly spot gracefully circling sparrow hawks, red-tailed hawks and small falcons. Adapting to City Life
WILDLIFE in urban settings sometimes adapt not only their behavior but also their physiology to the new environment.
In England, for example, one species of moth has changed from the white to black-winged variety, apparently to fit and survive better against sooty backgrounds. Blackbirds have been heard singing at night in London, perhaps because of the lights. Due to city warmth, they also are said to produce young 10 to 14 days earlier than rural blackbirds.
Foxes now have dens in everymajor American city in their climate zone. (There was even one under the bleachers of Yankee Stadium, John Rublowsky wrote in his bood, "Nature in the City.") But urban foxes seem to have duller senses, and they breed as much as three months earlier than their country cousins, researchers say.
The hedgehog, a porcupine-like creature in England that curls up and lies still when sensing danger, has begun to modify its behavior to cope with the automobile. Instead of playing possum, it now runs at the sound of an engine.
Animals in cities sometimes get urban diseases. Dogs in Philadelphia, for example, get cancer of the tonsils more often than their equals in adjacent rural regions.
Various types of urban wildlife can be health hazards to humans - from cockroaches, bats and rats to wild (and sometimes domestic) dogs and cats. Even aesthetically pleasing animals can be destructive to shrubs and structures. With rising numbers, they become real pests. Imported Trouble
MANY OF THE wildlife nuisances have intriguing histories.
Three of the peskiest birds - pigeons, house sparrows and starlings - were all deliberately imported to this country, for example.
Irridescent, pugnacious starlings, whose flocks darken the sunset in many big cities, are ancestors of 60 birds released in 1890 in New York's Central Park by a man who wanted all of the birds mentioned in Shakespear's writings to be found in North America.
Starlings are commuters in reverse, feeding in fields by day but preferring urban settings at night. They have pushed out bluebirds and other song birds from nests, and are even said to have ousted desert birds from nests in cactuses in the Southwest.
Similarly, the perky, curious house sparrows of today came from a single flock released in Brooklyn in 1852, for no known reason. The sparrow population peaked when the horse was the main engine of transportation, since feed grains, straw and even files were conducive to its flourishing.
The ubiquitous pigeon arrived with early settlers in the 1700s, perhaps to carry messages for the military or just as pets. It survives because of its great fertility and because it eats almost anything.
Also imported have been some exotic wildlife which accidentally got loose to become dangerous pests, mostly in Florida where the climate is hospitable.
Some 50 such animal species have been counted, according to the National Geographic Society. They include giant Colombian iguanas, walking Siamese catfish - 2-inch-long creatures with stiff fins that permit them to "walk" across roads - and the Amazon flesh-eating piranha, brought in under strict control but freed by craless handling.
Even rhesus monkeys, imported for early Tarzan films and later freed, survive in Florida swamps as curiosities.
In Florida, too, are western jackrabbits which escaped in 1940 from a training farm for racing greyhounds and which now have descended on the state's cattle ranches.
Armadillos, descendants of escapees from a private zoo in Cocoa Beach, Fla., that was destroyed in a 1924 hurricane, roam the Florida countryside. These animals, which ruin lawns by boring under them, are also invading from Mexico. They already are found in the Gulf states and as far north as Tennessee.