Surging Populations of Canada Geese and Deer
Some wildlife species have become urban dwellers mainly through human interference with their natural behavior. Such is the case with flocks of Canada geese that nest in suburban areas of the United States and stay put year round instead of migrating to Canada, as they normally would. This behavior change can be traced to the 1930's. Up to that time, hunters who shot wild geese and sold them to food stores kept large flocks of geese to use as decoys. They clipped the birds' primary flight feathers to prevent them from flying off and tethered them by lakes and ponds to lure migrating birds within shooting range.
But in 1935, the U.S. Congress outlawed live decoys, and within a few years, thousands of semidomesticated geese were turned loose. They joined flocks of captive-bred geese that federal and state game agencies had released on ponds for public enjoyment. By the 1950's, large flocks of nesting geese were spreading throughout the Northern states. Once they select a breeding site, they are faithful to it. Thus, within several generations, the geese lost whatever migratory instinct they still had. Today, young birds in these flocks travel only a few kilometers from their birth nests to set up breeding sites with lifelong mates. Coyotes and foxes sometimes kill nesting geese but not in sufficient numbers to slow their population growth.
Deer are not far behind geese in overrunning American suburbs. White-tailed deer range everywhere in the United States and Canada except parts of the Southwest. Mule deer dominate from the Rocky Mountains to the Pacific Coast. When settlers arrived in North America, the two species had an estimated population of 50 million. Because of land-clearing and intense hunting, white-tails numbered only about 500,000 by 1900, and mule deer even fewer. But by 1996, populations had risen to more than 15 million white-tails and about 6 million mule deer.
The major reason for their resurgence is a lack of natural predators—mainly wolves, which were virtually exterminated in the early 1900's, and a decrease in hunting. In the mid-1990's, several states launched programs to increase deer hunting, but cars probably "harvest" more deer than hunters do. Deer like the forest edge, and suburban environments mimic this habitat. They relish nibbling on fruit trees and many other popular plants in the suburban landscape. And they consider the produce in suburbanites' vegetable gardens gourmet fare. They quickly learn to avoid feeding when dogs and people are around to harass them.
