Controlling critters in golf-course landscapes
Golf courses make excellent habitat for many birds and mammals. For many golfers, seeing wildlife on the course adds to the beauty of the surroundings. However, the damage these animals cause to ornamentals and turfgrass on your golf-course is unsightly and expensive to repair. Once you've identified the species causing the problem, an integrated approach using a variety of management options provide effective long-term solutions.
Various animals, both large and small, are destructive. When these critters feed directly on shoots, stems or bark-or by burrowing and digging in the soil around plants-they cause damage.
Meadow voles Meadow voles are small, ground-dwelling rodents. Mature animals are about 7 inches long, with chestnut-brown fur on their backs and dark-gray fur on their underside. Voles have small, black eyes, and their ears are furred-and barely visible. It is important that you correctly identify mammals before starting control activities because materials or methods that are effective against one species may be useless against-or illegal-against another.
Grounds managers frequently confuse meadow voles with moles, shrews and pine voles. Moles have greatly enlarged front feet with prominent digging claws. Shrews have long, pointed snouts and pointed front teeth. Meadow voles have rounded, somewhat blunt snouts, and their front teeth are chisel-shaped. The distinction between meadow and pine voles is less obvious. The hind foot of the pine vole is about the same length as its tail. The tail of the meadow vole is twice the length of its hind foot.
Meadow voles prosper in grassy or weedy areas where ground cover is thick. Voles are active the entire year and create a system of surface runways about 1.5 inches wide. Overhanging vegetation along these runways provides the voles with protective cover. Their breeding potential is high-beginning in the spring and continuing into the fall. With suitable habitat, a few voles in spring can produce hundreds more by fall.
Strict vegetarians, voles leave bits of freshly cut plants in their runways that provide evidence of recent use. Typical vole foods include native grasses, legumes and herbaceous weeds-but they may also eat ornamental plants and flower bulbs. Small roots or mold in the runways indicate inactivity.
Meadow voles spend most of their time at or below ground level. However, during periods with deep snow, voles will surface and consume bark on trees and shrubs. Such feeding may result in complete girdling and death of plants. Fruit trees are particularly susceptible. You must reduce vole populations before the first snowfall or you put plants at risk the entire winter. Under snow cover, meadow voles travel freely without being seen or captured. When the snow melts, you may see evidence of runways in turf or grassy areas.
Vole control An integrated approach-using physical barriers and selective traps-will control vole numbers. Keep vegetation at least 2 feet away from trees by mowing, using herbicides, cultivating or using of a layer of gravel 2 to 3 inches deep.
Remove dead vegetation or thatch that may serve as cover and nesting material. Voles dislike areas of bare ground.
Wire guards made of 0.25-inch-mesh hardware cloth can prevent meadow-vole damage to small trees and shrubs. Cylinders, 24 inches high and about 6 inches in diameter, around trunks keep voles from girdling trees. The height of wire guards must be greater than anticipated snow depths, as voles may simply climb over the top of the guard. Areas where prolonged snowdrifts remain during winter may be especially susceptible to damage. These methods won't work against pine voles. You can best control them with rodentcides.
Trapping is a safe way to remove meadow voles. Set common mousetraps at burrow openings or in runways near ornamental shrubbery, flower beds, gardens or rock walls. Bait traps with cubes of fresh apple. Set them so the trigger lies across the runway then cover the trap with grass, leaves or an inverted cardboard box of appropriate size. Allow space for the trap to operate freely under the cover. Check traps during morning and evening and reset as needed until you don't capture any more voles-usually within 5 to 7 days.
The careful use of poison bait is appropriate for critter problems on golf courses. Most vole toxicants are restricted-use pesticides and are available only to certified applicators. Carefully follow all label instructions to protect non-target wildlife. The most selective and effective method is to hand-bait vole runs and holes with pellet baits. Distribute pellets into (not on top of) the grass cover, avoiding bare ground. Rain and snow reduce effectiveness. Consult your extension wildlife specialist for specific control recommendations. Moles Moles are small mammals that spend most of their lives in underground burrows. You can easily identify moles by their greatly enlarged, paddle-like forefeet and prominent toenails, which enable the animals to literally swim through the soil. Moles lack external ears, and their eyes are covered with skin, so you may think they don't have any. A mole's fur is soft and brownish to grayish with silver highlights. When brushed, the fur offers no resistance in either direction-enabling travel backward or forward within its burrows.
Moles inhabit woodlands, grasslands and turf. They construct extensive underground passageways and shallow, surface tunnels during spring, summer and fall and then deeper, permanent tunnels in winter. Actively feeding day and night-at all times of the year-they prefer insects (mature and larva), snails, spiders, small vertebrates and earthworms.
Moles prefer loose, sandy-loam soils and avoid heavy clays. Ridges of soil-which moles create when they construct runways as they forage for food-indicate mole activity. Mounds of soil appear on the surface as moles dig deep, permanent tunnels and nest cavities. In natural environments, moles cause little damage, and you'll seldom notice them-until their tunneling activity becomes apparent in turf areas. These tunnels make mowing difficult and can damage equipment.
Moles rarely eat flower bulbs or ornamentals while tunneling. They may indirectly damage vegetation, because they disturb plants as they search for insects. Moles don't establish themselves in areas where food isn't available. If you notice them, check your turf for grubs and other insects. If you do have moles, it may be comforting to know they aren't prolific breeders. Unlike mice and voles, moles only breed once a year and have litters of only three to four.
Mole control You can prevent moles from becoming established-and control them once they are-by improving soil-insect control. As mentioned, if food isn't available, moles won't hang around. Also, to remove the mole's food supply, you'll have to kill worms as well.
Trapping is an effective way to control moles. You can capture them by using harpoon, scissor-jawed and choker-type traps available from garden or hardware stores. Finding active runways is crucial for successful trapping. To determine if a runway is active, press down short sections of the raised ridges and mark these locations. Moles, as they travel, will repair that runway if it is active. They won't repair abandoned tunnels. Set traps only at the active locations and move them within 3 days if you fail to catch any moles. If you have the resources to do so, you can saturate an active area with traps, then move them to a new location after moles are captured.
Some toxicants are registered and available for mole control, but they are not always effective. Moles may not eat poison baits because of their preference for insects and grubs. Therefore, most authorities don't recommend rodenticides for controlling moles.
Skunks and other medium-sized digging mammals Skunks, armadillos and-to some degree-raccoons are after the same food as moles. These mammals also carry the possibility of rabies.
Skunks and raccoons are nocturnal and, while they do not hibernate, they may be inactive for extended periods during winter. They feed on fruits, berries and insects-often digging cone-shaped holes in turf to remove grubs. They may overturn insect-infested turf in large patches.
Skunk, armadillo and raccoon control Skunk fur (believe it or not) is valuable and, therefore, they have legal protection except during trapping seasons. Skunk, armadillo and raccoon activities rarely cause serious economic loss. In fact, they only dig when they are searching for-and finding-grubs.
To prevent these mammals from becoming established in buildings, seal all ground-level openings in building foundations and beneath porches, decks or crawl spaces should be sealed with concrete, sheet metal or heavy wire. If they are already under a building, close all openings except one and check the remaining opening for exit tracks after dark (dusting loose soil with talc or flour will make tracks more evident). If exit tracks appear, close that opening. You can also use one-way doors also for excluding these animals from structures. However, during May and June, their young may be left in the den unattended. Avoid sealing openings at that time because the young will starve and odor problems will result.
Because these are a rabies-vector species, their relocation is restricted in several states. We strongly advise that you get help from a licensed nuisance-wild life-control operator when trapping. You can obtain a list of nuisance trappers from state wildlife agencies or cooperative extension service offices. Gophers
Many people incorrectly identify several animals as gophers, including ground squirrels, moles and voles. But only a few kinds of "real" gophers exist, known as pocket gophers. Pocket gophers are about the size of a rat, 5 to 14 inches long. They spend almost their entire lives underground where they feed on plant roots. Gophers make themselves known by digging burrows to the surface and pushing out mounds of earth. These mounds are often in a line-indicating where the burrow is.
Gopher control You can place commercial gopher baits in the burrows by inserting a tube or rod into the turf, thereby penetrating the burrow. You then insert the bait into the holes so it falls into the burrow.
You can insert special gopher traps in the tunnel. Dig below the mound of earth on the surface to find them. Again, wildlife agencies can help you find traps and trappers to help with these problems.
Cottontail rabbits Rabbits prefer brushy cover interspersed with open, grassy areas. Fence rows, wooded stream banks and woodlands offer protective cover while adjacent vegetation provides summer food. Your golf-course landscape, with thickets of ornamental shrubs and hedgerows, are very attractive to them. In winter, rabbits clip twigs and gnaw the bark of woody plants. Golf courses provide excellent habitat-and few natural predators-for cottontails.
Rabbit control Rabbit-proof fences-about 24 inches high and made of 1-inch-mesh galvanized wire offer protection for small areas of high-value plants. Carefully stake the bottom edge of wire to the ground or bury several inches deep to prevent rabbits from getting under the fence.
Wire cages are effective in preventing damage to individual trees and shrubs during winter. Cylinders of 0.25-inch-mesh hardware cloth at least 24 inches high and set into the ground surrounding the trunk will help prevent gnawing on the trunk. Guards are not effective when snow depth exceeds the height of the wire. Also, it is important to remember that rabbits can reach bark on stems and lateral limbs about 20 inches above the depth of the snow.
Live trapping is helpful for removing individual animals causing damage. However, rabbits are protected game animals and relocation may require permits. Metal-cage traps are sold at some garden-supply stores, and apple slices are suitable baits.
No toxicants are registered for lethal control of rabbits. Repellents are usually a less-than-satisfactory method to protect plants from rabbit damage. However, natural repellants, such as fox urine, have provided effective control of rabbits, squirrels and other mentioned pests. You can buy it at sporting-goods stores and some lawn-and-garden supply stores. Spray it on wooden tongue depressors and insert them (repellant-end up) every 5 to 6 feet in the ground around the plants you want to protect. Re-apply it every 2 weeks as weather erodes effectiveness. Also, re-apply after rain, sleet, heavy fog or snow. Restrictions on the labels of nearly all rabbit repellents limit their use primarily to woody plants.
Woodchucks Woodchucks have compact, chunky bodies, supported by short, strong legs. Their tail is short and bristly and their forefeet have long, curved claws adapted for digging burrows. Woodchucks prefer to construct their burrows near hard structures such as rock piles, fences or building foundations where the combination of food and cover provides satisfactory habitat.
Woodchucks hibernate during winter months and emerge from their burrows in early February or March. Although they seldom venture far from their burrow, woodchucks may range up to 1 mile in their search for a new home or during breeding season.
Their den systems take much time and energy to construct. In early mornings and evenings during summer, woodchucks feed on green plants. A single animal can do tremendous damage to a small garden or flowerbed. They strip bark at the base of trees to mark their territories. Also, their burrows and mounds can damage reel mowers and other landscape equipment.
Woodchuck control Removing brush piles and mowing ditch banks will make areas less desirable for woodchucks and may expose them to their natural predators. As mentioned with larger varmints, seal all ground-level openings in buildings and under decks to prevent establishment.
Woodchuck-proof fences offer protection for small areas of high-value plants. Exclude them from flower gardens with a 24-inch-high fence of 1-inch-mesh galvanized wire. You may need a single strand of electric fencing about 6 inches above ground on the outside of the fence to prevent animals from climbing over or digging under this barrier. A two-strand electric fence with wires 6 and 12 inches above ground is also effective.
Lethal control can provide short-term relief from damage. However, young woodchucks often quickly reoccupy abandoned burrows. Studies have shown that nearly 80 percent of abandoned burrows may be reactivated within a couple of weeks during summer. You can use steel foothold, body-gripping or wire-edge traps if woodchucks are causing property damage. Apples are the best bait if you use a cage trap. Place body-gripping traps over the burrow entrance to capture them as they enter or leave. In any situation where you are concerned about capturing non-target animals or pets, use cage traps.
No federally registered repellents are available for reducing woodchuck damage to plants. Nor are any rodenticides labeled for woodchuck control.
Deer Although generally thought of as wildlife of forest and field, deer have become a common sight-and nuisance-on many golf courses.
Deer consume a variety of ornamentals. They eat woody twigs, buds and nuts during winter when other plants are not available. In addition, male deer cause damage to trees and shrubs when rubbing their antlers on trees and stems.
You can readily distinguish deer damage from that caused by rabbits or rodents. Deer leave a ragged, broken end on browsed branches-compared to the cleanly nipped terminal left by other wildlife. Summer damage to perennial flowers and gardens becomes more common when herd densities increase.
Deer control Deer can become very abundant in almost any habitat where they are not hunted. Hunting is an effective way to reduce deer population in areas where you can use bows or firearms. All states classify deer are as game animals. You can kill them only during legal hunting seasons after obtaining an appropriate license. Removing the females is essential for reducing deer numbers.
Fencing, wire cages and plastic netting are other methods you can use to reduce damage. Woven-wire fences 8 feet high are effective barriers but are cost-effective for only the most valuable ornamental plantings. Electric-fence designs are available that are less costly and almost as effective as tall, woven-wire fences. Physical barriers are the only effective means of preventing antler-rubbing damage.
Manufacturers have developed several deer repellents to protect woody ornamentals. They are most effective when you apply them before damage occurs and in situations where you expect plant losses to be light to moderate. Research has shown that some repellants reduce damage when applied every 4 to 5 weeks. You should apply repellents when temperatures are between 40 and 80 F and on days when you don't expect rain. However, repellants are not considered a long-term solution and may not always be practical on your golf course.
Combining an odor-based deer repellent with a simple, rope fence can prevent summer damage to bedding plants and perennials. Tie a rope on wooden or metal stakes about 30 inches aboveground surrounding the planting bed. Then tie cloth strips about 3 to 4 feet apart along the string and treat them with the repellent every 2 to 3 weeks.
At high densities (60 deer or more per square mile), few ornamentals grow that deer will not eat. You can obtain lists of deer-resistant plants from cooperative extension service offices or local garden clubs.
Geese Geese feed on aquatic plants and they desire water for security, but often they prefer to graze on the land. They leave vast amounts of droppings on greens and fairways. These droppings stick to shoes, block putts and can spread seed of undesirable turfgrasses and weeds. When they graze, geese can tear turf out by the roots.
Geese learn quickly where they are safe and where hunters cannot shoot them-on golf courses, parks, cemeteries and other protected land. Some populations have also abandoned flying south for the winter. Nowadays, they only fly as far as it takes to find open, non-frozen water.
Goose control The basic methods of control are scaring, controlling their habitat and removing them. The two most effective scaring methods are racket bombs and whistling cartridges fired from a small handgun. Keeping these tools in your pocket or cart-and using when necessary-is all that is required.
Alternative methods also are available for geese. Dogs, especially herding breeds (such as border collies) are well-suited for the task of scaring away geese. Once you've trained the dog, it's just a matter of instructing him to run after the geese. Not only is this enjoyable to watch, the dogs love to do it. The geese will initially fly into the water, but after repeated scaring, they will likely leave for a more peaceful habitat.
If you are able to do it, allowing grass to grow tall around water areas will discourage geese from hanging around. They don't like to walk through vegetation that is higher than 18 inches.
Geese are protected, and federal penalties could result without proper permits for hunting them.
Getting help The book Prevention and Control of Wildlife Damage is a valuable resource. (Contact 202 Natural Resources Hall, University of Nebraska, P.O. Box 830819, Lincoln, NE 68583-0819.) It has a section on sources of supplies. If you need local advice, your state extension wildlife specialist may have information. For technical assistance, contact the wildlife services office in your state. A growing number of private-sector wildlife-damage-control contractors are available who can take on your wildlife problems for a fee. Check your Yellow Pages for their phone numbers.
Dr. Paul D. Curtis is a professor in the Department of Natural Resources at Cornell University (Ithaca, N.Y.). Dr. Jeff Jackson is a professor of Wildlife Management at the University of Georgia (Athens, Ga.).
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