STARLING CONTROL METHODS

Ron J. Johnson Fig.1. European starlings (Sturnus vulgaris)
Extension Wildlife Specialist
Department of Forestry, Fisheries and Wildlife
University of Nebraska
Lincoln, NE 68583-0819

James F. Glahn
Research Wildlife Biologist
Denver Wildlife Research Center
USDA-APHIS-Wildlife Services
Mississippi Research Station
Mississippi State, Mississippi 39762-6099

Fig. 1. Starlings, Sturnus vulgaris

Legal Status

Damage Prevention and Control Methods

Exclusion
Fig.4. Bird-proof buildings to permanently eliminate bird problems inside.
Fig.4. Bird-proof buildings to permanently eliminate bird problems inside.

Close all openings larger than 1 inch (2.5 cm) to exclude starlings from buildings or other structures. This is a permanent solution to problems inside the structure (Fig. 4). Heavy plastic (polyvinyl chloride, PVC) or rubber strips hung in open doorways of farm buildings have been successful in some areas in excluding birds while allowing people, machinery, or livestock to enter. Hang 10-inch (25-cm) wide strips with about 2.0-inch (5-cm) gaps between them. These strips might also be useful for protecting feed bunks. Netting over doorways may also exclude birds from buildings, but would be easily torn by machinery or livestock.

Fig.5. A wooden metal, or plexiglass covering over a ledge at a 45 degee angle (a) or porcupine wire (b) can be used to proevent roosting and nesting.
Fig. 5. A wooden, metal, or plexiglass covering over a ledge at a 45o angle (a) or porcupine wires (b)
can be used to prevent roosting and nesting.
Fig. 6. Neting can be used to exclude birds from building rafters and from fruit trees.
Fig. 6. Netting can be used to exclude birds from building rafters and from fruit trees.

Where starlings are roosting or nesting on the ledge of a building, place a wooden, metal, or plexiglass covering over the ledge at a 45font-size:5.7pt; o angle to prevent use (Fig. 5). Metal protectors or porcupine wires (Nixalite® and Cat Claw®) are also available for preventing roosting on ledges or roof beams.

Nylon or plastic netting is another option for exclusion (Fig. 6). Exclude starlings that are roosting inside open farm buildings by covering the underside of the roof beams with netting. Netting is also useful for covering fruit crops such as cherries or grapes to prevent bird damage, and studies show it to be a cost-effective method of protecting higher-value grapes in commercial vineyards. For wine grapes harvested one time per season, tractor-mounted rollers can facilitate installation and removal of netting draped directly over vines. Some New York vineyards have used this method for five years with the original netting still in good condition. For table grapes harvested by hand several times per year, a frame can be used to hold the netting above the vines so it doesn’t interfere with the frequent harvests. A practical tip: if protecting the total vineyard is impractical, protect varieties that receive the most damage, those that ripen early or are otherwise highly attractive to birds (for example, small, dark, sweet grapes.)

Where starlings compete with other birds for nest boxes, proper nest box construction helps. For bluebird boxes, use a round 1 1/2-inch (3.8-cm) hole or a rectangular slot, 4 inches (10 cm) wide by 1 1/8 inches (29 mm) high, to allow bluebirds in but keep starlings out. Starlings are discouraged by horizontal wood duck nest boxes made from a 24-inch (61-cm) section of 12-inch-diameter (30.5-cm) stove pipe. The ends are made from wooden circles, and the entrance hole on one end is semicircular and 4 inches (10 cm) high by 11 inches (28 cm) wide. Other nest box features such as interior dimensions and color, amount of light allowed into the box, and box placement appear to have potential for discouraging starlings while encouraging preferred cavity-nesters.

Cultural Methods and Habitat Modification

Livestock Facilities. Starlings are attracted to livestock operations by the food and water that is available to them. Feedlots offer an especially attractive food source to starlings during winter when snow cover and frozen ground impede their normal feeding in open fields or other areas. The snow cover and frozen ground increase the likelihood as well as the severity of damage.

Some livestock operations are more attractive to starlings than others. Operations that have large quantities of feed always available, especially when located near a starling roost, are the most likely to have damage problems. Research results emphasize the importance of farm management practices in long-term starling control. These practices limit the availability of food and water to starlings, thus making the livestock environment less attractive to birds. The following practices used singly, but preferably in combination, will reduce feed losses, the chance of disease transmission, and the cost and labor of conventional control measures.

1. Clean up spilled grain.

Fig. 7. Use bird-proof facilities to store grain.
Fig. 7. Use bird-proof facilities to store grain.

2. Store grain in bird-proof facilities (Fig. 7).

3. Use bird-proof livestock feeders. These include flip-top pig feeders, lick wheels for liquid cattle supplement, and automatic-release feeders (magnetic or electronic) for costly high-protein rations. Using covered feeders prevents starling access and contamination of the food source, and the banging of the lift-top lids as pigs use the feeders may frighten starlings and keep them uneasy. Avoid feeding on the ground because this is an open invitation to starlings.

4. Where possible, feed livestock in covered areas such as open sheds because these areas are less attractive to starlings.

5. Use feed forms that starlings cannot swallow, such as cubes or blocks greater than 1/2 inch (1.3 cm) in diameter. Minimize use of 3/16 inch (0.5 cm) pellets; starlings consume these six times faster than granular meal.

6. When feeding protein supplements with other rations, such as silage, mix them well to limit starling access to the supplements.

Fig. 8. Lower the water level in livestock waterers so starlings cannot reach the water when perching on the edge. At the same time, keep the water level deep enough so they cannot stand in the waterer.
Fig. 8. Lower the water level in livestock waterers so starlings cannot reach the water when perching on the edge. At the same time, keep the water level deep enough so they cannot stand in the waterer.

7. Where possible, feed livestock in covered areas such as open sheds because these areas are less attractive to starlings. Use feed forms that starlings cannot swallow, such as cubes or blocks greater than 1/2 inch (1.3 cm) in diameter. Minimize use of 3/16 inch (0.5 cm) pellets; starlings consume these six times faster than granular meal. When feeding protein supplements with other rations, such as silage, mix them well to limit starling access to the supplements. Where possible, adjust feeding schedules so that exposure of feed to birds is minimized. For example, when feeding once per day, such as in a limited energy-feeding program for gestating sows, delay the feeding until late in the afternoon when foraging by starlings is decreased. Feed cattle at night if possible. Starlings prefer to feed early to midday and in areas where feed is constantly available. Feeding schedules that take these factors into account minimize problems.

8.Starlings are especially attracted to water. Drain or fill in unnecessary water pools around livestock operations. Where feasible, control the water level of livestock waterers to make them unavailable or less attractive to starlings (Fig. 8).

Tree Roosts. When roosts occur in a small number of landscape trees near homes or along streets, thinning branches from the trees used by birds will usually disperse them. Roosts in tree groves or woodlots usually occur in dense, overcrowded stands of young trees. Remove about one-third of the trees to improve the tree stand, especially if marked by a professional forester, and to disperse the birds. Such thinning successfully dispersed roosts from research woodlots in Ohio and Kentucky, and from at least two problem-roost situations in Nebraska. In dense cedar thickets, bulldozing strips through the roost to remove one-third of the habitat has also been successful in dispersing birds. Soil disturbance, however, may be hazardous if soils harbor fungal spores of the human respiratory disease histoplasmosis. For further information on roost dispersal, see Bird Dispersal Techniques.

Frightening

Frightening is effective in dispersing starlings from roosts, small-scale fruit crops, and some other troublesome sites. It is useful around livestock operations that have warm climates year-round, and where major concentrations of wintering starlings exist. In the central states, starlings concentrate at livestock facilities primarily during cold winter months when snow covers natural food sources. At this time, baiting and other techniques are generally more effective than frightening. In addition, frightening starlings may disperse birds to other livestock facilities, a negative point that should be considered if disease transfer is a concern.

Frightening devices include recorded distress or alarm calls, gas-operated exploders, battery-operated alarms, pyrotechnics (shellcrackers, bird bombs), chemical frightening agents (see Avitrol® below), lights (for roosting sites at night), bright objects, and various other stimuli. Some novel visual frightening devices with potential effectiveness are eye-spot balloons, hawk kites, and mylar reflective tape. Ultrasonic (high frequency, above 20 kHz) sounds are not effective in frightening starlings and most other birds because, like humans, they do not hear these sounds.

Harassing birds throughout the evening as they land can be effective in dispersing bird roosts if done for three to four consecutive evenings or until birds no longer return. Spraying birds with water from a hose or from sprinklers mounted in the roost trees has helped in some situations. Beating on tin sheets or barrels with clubs also scares birds. A combination of several scare techniques used together works better than a single technique used alone. Vary the location, intensity, and types of scare devices to increase their effectiveness. Two additional tips for successful frightening efforts: 1) begin early before birds form a strong attachment to the site, and 2) be persistent until the problem is solved. For a more detailed discussion of frightening techniques, see Bird Dispersal Techniques.

Avitrol®. Avitrol® (active ingredient: 4-aminopyridine) is a Restricted Use Pesticide available in several bait formulations for use as a chemical frightening agent. It is for sale only to certified applicators or persons under their direct supervision and only for those uses covered by the applicator’s certification.

Avitrol® baits contain a small number of treated grains or pellets mixed with many untreated grains or pellets. Birds that eat the treated portion of the bait behave erratically and/or give warning cries that frighten other birds from the area. Generally, birds that eat the treated particles will die. Avitrol® baits are available for controlling starlings at feedlots and structures. At the dilution rates registered for use at feedlots, there is a low but potential hazard to nontarget hawks and owls that might eat birds killed by Avitrol®. It is therefore important to pick up and bury or incinerate any dead starlings found.

Around livestock operations, Avitrol® is sometimes used where the goal is to frighten or disperse the birds rather than to kill them. However, many birds may be killed, and data are lacking on whether the results of Avitrol® use at feedlots occur because of frightening aspects or from direct mortality.

Three Avitrol® formulations are labeled for starling control at feedlots (Pelletized Feed, Double Strength Corn Chops, and Powder Mix). The formulation most appropriate for a given situation may vary, particularly if large numbers of blackbirds are mixed with the starlings. However, the Pelletized Feed formulation is generally recommended for starling control because starlings usually prefer pellets over cracked corn (corn chops). The Double Strength Corn Chops formulation is probably best for mixed flocks of starlings and blackbirds. Because Avitrol® is designed as a frightening agent, birds can develop bait shyness (bait rejection) fairly quickly. Prebaiting for several days with untreated pellets may be necessary for effective bait consumption and control. If starling problems persist, changing bait locations and additional prebaiting may be needed. If any Avitrol® baits are to be used, contact a qualified person trained in bird control work (someone from USDA-APHIS-Wildlife Services or Cooperative Extension, for example) for technical assistance.

Repellents

Soft, sticky repellents such as Roost-No-More®, Bird Tanglefoot®, 4-The-Birds®, and others consist of polybutenes, a nontoxic material that can be useful in discouraging starlings from roosting on sites such as ledges, roof beams, or shopping-center signs. It is often helpful to first put masking tape on the surface needing protection, then apply the repellent onto the tape; this increases effectiveness on porous surfaces and makes removal easier. Over time, these materials lose their effectiveness and have to be replaced.

Recent research has found that flavoring used in grape soft drinks, dimethyl anthranilate (DMA), and methyl anthranilate (MA) repel starlings from livestock feed at rates that do not affect cattle. Although subsequent field trials showed that DMA may not be cost-effective in some situations, results have indicated that MA has potential for cost-effective starling repellency.

Research is ongoing to improve the cost-effectiveness of this compound and to develop its potential for managing starlings at livestock facilities and possibly for repelling birds from fruit crops.

Toxicants

When using toxicants or other pesticides, always refer to the current pesticide label and follow its instructions as the final authority on pesticide use.

Starlicide. A chemical compound developed for starling control during the 1960s by the Denver Wildlife Research Center is now commercially available as a pelletized bait. It is sold under the trade name Starlicide Complete (0.1% 3-chloro p-toluidine hydrochloride).

Starlicide is a slow-acting toxicant for controlling starlings and blackbirds around livestock and poultry operations. It is toxic to other types of birds in differing amounts, but will not kill house (English) sparrows (Passer domesticus) at registered levels. Mammals are generally resistant to its toxic effects.

Poisoned birds experience a slow, nonviolent death. They usually die from 1 to 3 days after feeding, often at their roost. Generally, few dead starlings will be found at the bait site. Poisoned starlings are not dangerous to scavengers or predators. However, to provide good sanitation and to prevent the spread of diseases that the birds may carry, pick up and bury or incinerate any dead starlings.

It is important to use fresh bait, as the current formulation of Starlicide Complete loses effectiveness in storage. Bait kept on hand from one winter to the next may lose some of its potency, and bait kept for 2 years may not work at all.

How to Use. Field tests in both the western and eastern United States have established guidelines for using Starlicide. For the best success in a control program, we recommend the following steps:

1. Observe birds feeding in and around the livestock operation. Note the number of starlings and when and where they prefer to feed. The best time for observing is usually during the first few hours following sunrise when birds are seeking their morning meal.

2. Determine what species of birds are feeding. If any protected birds, such as doves, quail, pheasants, or songbirds, are present, do not apply toxic bait. For assistance or advice on bird identification or nontarget risk assessment based on the situation, contact your local Cooperative Extension office, USDA-APHIS-Wildlife Services office, or the state wildlife agency.

3.Prebait, for best results, with a nonpoisonous bait to accustom starlings to feeding on bait at particular locations. Place the prebait in areas where the starlings concentrate to feed, but where it will not be accessible to livestock or other nontarget animals. The best prebait is a high-quality food that resembles the toxic bait in color, size, and texture. If such prebait is unavailable, use a good quality feed such as that normally fed to livestock. Prebait for 1 to 4 days until the birds readily feed on the prebait. If good consumption is not obtained, move the prebait to another location where starlings are concentrating to feed.

4. Apply prebait and bait on cold days when snow covers the ground. This timing is more effective because starlings become stressed for food and concentrate in livestock feeding areas.

Fig.9. Well-positioned bait containers, excluded from livestock, provide better safety and control in baiting programs for starlings.
Fig. 9. Well-positioned bait containers, excluded from livestock, provide better safety and control in baiting programs for starlings.

5. Place prebait and bait in containers to ensure proper bait placement and to protect it from the weather (Fig. 9). Black rubber calf feeder pans work well. They do not tip easily, their dark color does not frighten birds, and bait is openly exposed. Empty farm wagons, feeder lids turned upside down, wooden troughs, or other containers may also work. Avoid brightly colored or shiny containers or ones that might tip and spill bait. At night, the containers can be covered to protect the bait from the weather. However, they must be uncovered at dawn so that starlings can feed as soon as they arrive. At feedlots where large numbers of starlings (more than 100,000) are involved, and where large quantities of feed are available on the ground, broadcasting bait in alleyways as per label directions is recommended.

6. Apply toxic bait after starlings feed readily on the prebait by removing all prebait and replacing it with the toxic bait. Consult the label directions for the amount to use (1 pound [0.45 kg] of Starlicide Complete used properly will kill about 100 to 200 starlings). The total number of starlings using a farm over a long period of time may greatly exceed the numbers observed on a given day, so continue baiting for at least 2 or 3 days or until bait consumption diminishes. Bait should be available to the starlings at all times when they are present.

Good bait acceptance may be more difficult to obtain in warm-weather climates such as in the southernmost states. If this occurs, and the Starlicide Complete bait is not eaten, an alternative may be to use Starlicide Technical (98% active ingredient) applied to baits such as french-fried potatoes, small fruits, or livestock feed according to label directions. The french fries and fruits may be more attractive to starlings, but they can spoil rapidly. Generally, livestock feed makes an acceptable bait because starlings are accustomed to feeding on it. Starlicide Technical can be used only by or under supervision of the USDA-APHIS-Wildlife Services for control of blackbirds and starlings at livestock operations. Contact them for help.

7. Remove bait after bait consumption diminishes. Observe any birds arriving at the feedlot during the next 2 to 3 mornings after baiting. Reduced bird numbers at this time indicate control, as most birds will die at the roost. If starlings continue to be present, or if they gradually return in increasing numbers, wait until a number of birds are regularly returning to feed at the area. Then apply prebait and toxic bait (Steps 4 to 6) as before. Do not leave Starlicide baits exposed for prolonged periods because this may cause bait shyness (bait rejection), and may also increase hazards to protected bird species.

8. Group baiting may increase effectiveness. Consider coordinating control efforts with your neighbors. Several persons baiting at the same time will produce better control because starlings may forage over a large geographical area and may change feeding sites from day to day. Notify local wildlife officials of your plans so that if large numbers of starlings are removed, the officials will be able to explain the die-off. Contact USDA-APHIS-Wildlife Services officials about the possibility of using roost control procedures if a large roost is associated with the damage problem.

9. Cautions: Starlicide is poisonous to chickens, turkeys, ducks, and some other birds. Never expose bait where poultry, livestock, or nontarget wildlife can feed on it. Do not repackage pesticides into anything other than their original containers. Read and follow all label directions.

Toxic Perches. Toxic perches are perforated metal tubes 24 or 27 inches (61 or 69 cm) long containing a wick saturated with a contact toxicant that enters the feet as the birds perch on the tube. They can be safely and effectively used in certain industrial and other structural roost situations where they do not present hazards to nontarget birds and avian predators such as hawks and owls. All killed birds should be picked up immediately and buried or burned because of potential hazards to other wildlife.

The active ingredient in toxic perches, fenthion (Rid-A-Bird Perch 1100 Solution), is federally registered as a Restricted Use Pesticide for use in these perches. Fenthion is rapidly absorbed through the skin and should be used with caution to avoid spillage and exposure to the handler. It is toxic to humans, birds, fish, and aquatic invertebrates. For additional information on fenthion, refer to Pesticides. [Editor's note: This product is no longer available]

Agents for Roost Control. Roost control has been used to reduce starling damage at livestock feedlots and in urban areas where there are human health and sanitation concerns. A recent study indicates, however, that roost control with wetting agents (no longer registered) may not consistently provide long-term reduction of birds at feedlots, despite mostly favorable results in reducing urban problems. The presence of other roosting populations near the treated roost may be an important factor. At urban sites having mild winter climates, the accumulation of bird carcasses can produce a severe odor and fly problem if carcasses are not picked up or buried at the site soon after roost treatment. Bulldozing sites is the most efficient method to bury carcasses, but soil disturbance during this process may present human health hazards from dissemination of histoplasmosis spores. Such roost control should be considered only as a last resort when other alternatives are not likely to solve the problem in livestock and urban roost situations.

Currently, the only material registered for roost control is Starlicide Technical, which is used for baiting at or near roost sites in areas where starlings congregate before roosting. This method is currently registered for use in only a few states and only under supervision of USDA-APHIS-Wildlife Servcies personnel. A federal registration is pending. Although this method of roost control is labor-intensive, it has been effective.

Fumigants

Fumigation is generally not practical for starling control, and no fumigants are registered for this purpose.

Trapping

Trapping and removing starlings can be a successful method of control at locations where a resident population is causing localized damage or where other techniques cannot be used. An example is trapping starlings in a fruit orchard.

Two types of traps, nest-box and decoy traps, are commonly used. Nest-box traps (Fig. 10) are successful only during the nesting season, whereas decoy traps (Fig. 11) are most effective during other times when the birds are flocking. Nontarget birds captured in traps should be immediately released unharmed.

Fig. 10. Nest-box trap for starlings. Fig. 11. Starling decoy trap: (a) assembled view and (b) details of the entrance panel. Side and end

Decoy traps for starlings should be at least 5 to 6 feet (1.5 to 1.8 m) high to allow for servicing and can be quite large (for example, 10 feet [3 m] wide by 30 feet [9 m] long). A convenient size is 6 x 8 x 6 feet (1.8 x 2.4 x 1.8 m) (Fig. 11). If desired, the sides and top can be constructed in panels to facilitate transportation and storage. In addition, decoy traps can be set up on a farm wagon and thereby moved to the best places to catch starlings. Place traps where starlings are likely to congregate. Leave a few starlings in the trap as decoys; their feeding behavior and calls attract other starlings that are nearby. Decoy birds in the trap must be well watered (which may include a bird bath) and fed. A well-maintained decoy trap can capture 100 or more starlings per day depending on its size and location, the time of year, and how well the trap is maintained. Euthanize captured starlings humanely such as by carbon dioxide exposure or cervical dislocation.

Shooting

Shooting is more effective as a dispersal technique than as a way to reduce starling numbers. The number of starlings that can be killed by shooting is very small in relation to the number of starlings usually involved in pest situations. Shooting, however, can be helpful to supplement and reinforce other dispersal techniques. For more detail on dispersal, see Bird Dispersal Techniques.

Editors

Scott E. Hygnstrom; Robert M. Timm; Gary E. Larson

Prevention and Control of Wildlife Damage Logo 1994

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994

Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska -Lincoln

United States Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control

Great Plains Agricultural Council Wildlife Committee

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