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9 Squirrel Problems (from a human viewpoint)
- Johns Hopkins University Press
- Chapter
- Additional Information
Are squirrels pests? They can be. In a 2003 New York Times article, Elisabeth Bumiller describes how squirrels living on the White House lawn killed an historic tree. It seems the squirrels stripped so much bark off the upper limbs of a buckeye tree planted by Theodore Roosevelt that it died and had to be cut down. Bark stripping is common practice among many temperate tree squirrels and some ground squirrels. Squirrels strip away the top layer of the bark to get to the sweet, phloem tissue underneath. This occurs most commonly in early summer and can be fatal to trees, either by killing them outright or by making them susceptible to infestation by insects or fungi. Bark stripping, though relatively innocuous in wild forests, can seriously damage managed forests, which tend to have thousands of acres of a single species of similaraged trees growing together. Squirrels prefer to debark trees of a certain diameter (less than 6 cm or 2.4 inches), and when many trees of this size are located together, the damage can be significant. Besides the risk of killing a tree, bark stripping can stunt a tree’s growth and cause deformations in the wood, both of which can decrease the tree’s usability by timber companies. With estimates of 30–90% damage in certain stands of trees, bark stripping can affect companies negatively. In fruit orchards, woodchucks also strip bark. In this case, they gnaw on the lower bark of trees, and studies show that trees that have been gnawed upon produce smaller and fewer fruits than ungnawed trees. In tropical plantations tree squirrels are considered unwelcome pests, Chapter 9 Squirrel Problems (from a human viewpoint) because they feed extensively on ripe fruit, cocoa, and palm nuts. In central and northern South America, the red-tailed squirrel (Sciurus granatensis) is a common pest on cocoa plantations, and in Southeast Asia, multiple species of Callosciurus commonly invade plantations. In Kenya, the striped ground squirrel (Xerus erythropus) frequently preys on maize seeds and crops, which can account for more than half the damage to all maize crops. In North America, some ground squirrels also are considered agricultural pests and are known to damage many grain crops through extensive feeding. In 1910, a U.S. Department of Agriculture publication estimated that ground squirrels were responsible for more than $10 million dollars of damage per year to crops. (Today, that would be equal to approximately $200 million in damage.) A 1999 report found that Belding’s ground squirrels feeding on alfalfa crops in northeastern California caused significant damage, costing farmers on average $402 per hectare. Prairie dogs have been considered pests by ranchers in the western United States for more than a century. Ranchers claim that prairie dogs compete with livestock for food and that prairie dog burrows pose a danger to livestock and machinery. Starting at the turn of the twentieth century , ranchers, with the support of the U.S. government, began systematically killing prairie dogs using any means possible. Prairie dogs were shot, trapped, and poisoned by the hundreds of thousands. This assault, combined with the unintentional introduction of plague from Asia, resulted in an extreme reduction in prairie dog populations and their extirpation from many areas. Today, prairie dogs occupy only a fraction of their historical range (though estimates of the size of their historical range are controversial ). In recent studies biologists have found that the supposed damage done by prairie dogs has been overstated, but the view of the prairie dog as pest is deep-rooted and still persists today. While two species of prairie dogs, the Mexican and Utah, have some legal protection, white-tailed and blacktailed prairie dogs do not, and attempts to gain protection for these species have been contentious and highly political. In suburban areas, humans intentionally and unintentionally provide a plethora of tasty treats for squirrels. Buds, shoots, flowers, bulbs, fruits, and vegetables are all part of a successful suburban squirrel’s diet, much to many a gardener’s dismay. Squirrels readily dig up flower bulbs and will quickly remove every last tomato from a ripe vine. Squirrels frequently show up uninvited at many backyard bird feeders, quickly emptying them, and moving on. Woodchucks, also common in suburban areas, make snacks of fresh garden greens whenever possible. Municipal parks offer havens for squirrels in the middle of urban areas. The absence of many predators, combined with supplemental feeding by Squirrel Problems 125 [44.197.113.64] Project MUSE...