Nuisance Wildlife Species
North America’s largest rodent, the American beaver, exhibits a wide range of physical adaptations to its largely aquatic lifestyle. The heavily muscled body is shaped more like a marine mammal than like other terrestrial mammals, while the hind-feet are webbed for swimming. Furthermore, the characteristically flattened, scaly tail provides steering and propulsion, particularly when swimming fast or diving. While the colouration of the coarse outer-fur varies from chestnut to almost black, the dense underfur is typically dark grey and maintains body warmth even in freezing waters. The ears and nose are equipped with valve-like flaps that can be closed underwater, while the small eyes have a protective transparent eyelid (nictitating membrane). Owing to the need for a strong foundation for the prominent tree-felling incisors, the beaver has an exceptionally thick and heavy skull and jaw. Large claws on the short forefeet provide dexterity with handling food and also facilitate digging. As many as 24 subspecies of the American beaver are recognised, but reintroductions have blurred their geographic boundaries and resulted in genetic mixing. (1)
The raccoon (Procyon lotor) is a native mammal, measuring about 3 feet long, including its 12-inch, bushy, ringed tail. Because their hind legs are longer than the front legs, raccoons have a hunched appearance when they walk or run. Each of their front feet has five dexterous toes, allowing raccoons to grasp and manipulate food and other items. Raccoons prefer forest areas near a stream or water source, but have adapted to various environments throughout Washington. Raccoon populations can get quite large in urban areas, owing to hunting and trapping restrictions, few predators, and human-supplied food. Adult raccoons weigh 15 to 40 pounds, their weight being a result of genetics, age, available food, and habitat location. Males have weighed in at over 60 pounds. A raccoon in the wild will probably weigh less than the urbanized raccoon that has learned to live on handouts, pet food, and garbage-can leftovers. As long as raccoons are kept out of human homes, not cornered, and not treated as pets, they are not dangerous. (2)
Most species of North American bats are insectivorous, have only one young per year in early summer, and hibernate during the winter (Barbour and Davis 1969). A few species are dependent on nectar and pollen for food, and several species undertake moderately long autumnal migrations to the south where their food resources are available in winter. Many bats roost in natural situations such as trees, rock crevices, and caves, but many also use buildings, bridges, and mines. Bats forage for food after darkness falls, in cities and towns and over fields and lakes. We often see them swooping around lights where they exploit dense clouds of insects that are attracted to the lights. Average lifespan for most North American bats is in the range of 5-10 years, and some have lived as long as 30 years (Hill and Smith 1984). They truly are not like rodents, with which they are frequently compared, and which are short-lived and reproduce prolifically. Bats seem to have evolved as moderately long-lived, intelligent creatures with a low reproductive potential and specialized senses, such as echolocation, that allow them to exploit the resources of the night. Bats in North America belong to four different families: Mormoopidae, Phyllostomidae, Vespertilionidae, and Molossidae. (3)
Like many other armadillos, nine-banded armadillos are covered by an outer body armor made up of bony plates covered in a leathery keratinous skin. These scales (osteoderms) provide a hard but flexible covering. The scales are typically rectangular or pentagonal in shape and are developed later than the rest of the skeleton. The armor comprises about 16% of body weight and is divided into three main areas of coverage on the body: a pelvic shield, a shield on the shoulder region, and the characteristic bands of the back. Typically, nine-banded armadillos have 9 visible bands, but this number may vary from 8 to 11. Each band is separated by a thin layer of skin and hairs. Scales grow continuously and wear, but are never fully shed. The average body length is 0.752 m. The tail averages about 0.3 m in length and is covered by 12 to 15 rings of scales. (4)
Moles are small, destructive burrowing creatures about five to eight inches long. Weighing in around three to five ounces, moles have thick bodies with short, velvety fur that conceals their extremely small ears and eyes. On average, moles live for two to three years. Moles are often noted for their enlarged, webbed feet, which they use as paddles to “swim” through soil. As they move deftly and swiftly underground, they leave behind unsightly trails that can disfigure and uproot flowers, plants, crops and shrubs. These trails can also be quite hazardous to homeowners. Just ask anyone who has had the misfortune to trip over a mole run and sprain an ankle. Moles are active year round, 24/7, though they tend to be most active in the spring and fall. Generally, moles will create surface tunnels or ridges in the top 6 to 12 inches of the ground as this contains the largest food supply. During the winter, moles burrow deeper into the soil as their food source burrows deeper, in search of food. (5)
Skunks are mild-tempered, mostly nocturnal, and will defend themselves only when cornered or attacked. Even when other animals or people are in close proximity, skunks will ignore the intruders unless they are disturbed. Skunks are beneficial to farmers, gardeners, and landowners because they feed on large numbers of agricultural and garden pests. Two skunk species: The striped skunk is the size of a domestic cat, ranging in length from 22 to 32 inches, including its tail. Its fur is jet black except for two prominent white stripes running down its back. The striped skunk occurs throughout most lowland areas in Washington, preferring open fields, pastures, and croplands near brushy fencerows, rock outcroppings, and brushy draws. It is also seen—or its musky odor noticed—in some suburban and urban locations, particularly near sources of open water. The spotted skunk, also known as the polecat, ranges in length from 14 to 18 inches, including its tail. Its fur is a black or grayish black, with white stripes on its shoulders and sides, and white spots on its forehead, cheeks, and rump. The spotted skunk occurs throughout west and southeast Washington. The spotted skunk and striped skunk use similar types of habitat, although the spotted skunk is more likely to be seen in and around forests and woodlands, and is not as tolerant of human activity as the striped skunk. (6)
Grey Squirrels – Two species of gray squirrels inhabit the United States, the western gray and the eastern gray. The eastern gray squirrel normally inhabits the northeastern United States, although it has invaded the western United States, as well as Europe. The western gray squirrel lives in three separate locations along the western coast. Both of these large squirrels appear in a variety of colors, which include black, gray, brown, cream and red.
Fox Squirrels – Fox squirrel species live throughout most of the United States, excluding the eastern coast. It is the largest type of squirrel ranging from 17 to 27 inches long. These large squirrels come in two distinct color groups. One has dark fur in variable shades from black to gray and tan or gold undersides. These dark-colored squirrels have black heads with white noses, ears and feet. The other color is reddish, tan or orange. The red fox squirrels have no white markings.
Red Squirrels – Little red squirrels are about half the size of gray squirrels. These small tree squirrels have fur that is gray-red in the winter and orange-red in the summer with a white belly. During the winter months, red squirrels will grow tufts of fur on their ears. When other animals enter their territory, they tend to chatter or whistle loudly at such invaders. Red squirrels, also known as pine squirrels, live in the colder northern states and prefer living in pine forests.
Flying Squirrels – The United States is home to two species of flying squirrels, the northern flying squirrel and the southern flying squirrel. The northern flying squirrel is the larger of the two squirrel species. Usually, it lives in the higher elevations of Alaska, California, Arizona, Michigan and the Appalachian and Adirondack mountains. Southern flying squirrels are found in the eastern half of the United States in lower elevations down through Florida (wild). These very small squirrels may outnumber gray squirrels, although their nocturnal living habits make them nearly impossible to find. (7)
Urban coyotes are coyotes that reside in North America, usually metropolitan areas (major cities and their suburbs). Coyotes thrive in suburban settings and even some urban regions, because of the availability of food and the lack of predators. One report described them as “thriving” in U.S. cities, and a 2013 report in The Economist suggested that urban coyotes were increasingly living in cities and suburbs. Unlike rural coyotes, urban ones have a longer lifespan and tend to live in higher densities, but rarely attack humans, according to one report. The animals generally are nocturnal and prey upon rabbits, rats, Canada geese, fruit, insects and family pets, especially small dogs and domestic cats. Coyotes were reportedly living underneath decks in suburban Stamford, Connecticut and in some instances chasing after large dogs. A researcher studying the impact of coyotes in the city of Austin, Texas found that urban coyote management techniques, including steps to trap and remove coyotes who were exhibiting bold or aggressive behavior, as well as efforts to educate the public about not feeding the animals, had had a positive effect in lessening possible risk to humans or to pets. (8)
The red fox (Vulpes vulpes) is the most common of the foxes native to North America. Most depredation problems are associated with red foxes, although in some areas gray foxes (Urocyon cinereoargenteus) can cause problems. Few damage complaints have been associated with the swift fox (V. velox), kit fox (V. macrotis), or Arctic fox (Alopex lagopus).
The red fox is dog-like in appearance, with an elongated pointed muzzle and large pointed ears that are usually erect and forward. It has moderately long legs and long, thick, soft body fur with a heavily furred, bushy tail (Fig. 1). Typically, red foxes are colored with a light orange-red coat, black legs, lighter-colored underfur and a white-tipped tail. Silver and cross foxes are color phases of the red fox. In North America the red fox weighs about 7.7 to 15.4 pounds (3.5 to 7.0 kg), with males on average 2.2 pounds (1 kg) heavier than females.
Gray foxes weigh 7 to 13 pounds (3.2 to 5.9 kg) and measure 32 to 45 inches (81 to 114 cm) from the nose to the tip of the tail (Fig. 1). The color pattern is generally salt-and-pepper gray with buffy underfur. The sides of the neck, back of the ears, legs, and feet are rusty yellow. The tail is long and bushy with a black tip.
Other species of foxes present in North America are the Arctic fox, swift fox, and kit fox. These animals are not usually associated with livestock and poultry depredation because they typically eat small rodents and lead a secretive life in remote habitats away from people, although they may cause site-specific damage problems. (9)
Yellow Jackets – These highly aggressive stinging insects develop large colonies that are fervently defended. As a result, intruders can be swarmed in a matter of minutes, often getting stung hundreds of times. These insects are especially fond of foraging in and around trash piles and garbage cans. They are a common invader to outdoor picnics.
Bald-faced Hornets – These wasps (yes — despite their name – they are wasps) would be harmless but only if you can completely steer clear of their nests. However, a number of cues can trigger a swarm to attack. Those can include approaching within three feet, loud noises, vibrations, jostling the nest or unexpected visual changes in the environment. When a colony goes into attack mode, individual wasps sting and inject venom into their target. If they cannot reach the target (if they are separated by a screen, for example) the bald-faced hornets will squirt venom into the eyes of the perceived threat.
Carpenter Bees – These bees are primary pollinators and common visitors to suburban flowerbeds. When threatened, these bees make a show of aggression but rarely sting. In fact, in many species of carpenter bee the males have no stinger at all. The only real threat carpenter bees pose is to wood structures – they will bore holes in wood to create chambers for egg laying. (10)