EUROPEAN STARLINGS

This starling is native to most of Eurasia, but has been introduced to South Africa, North America, Australia and New Zealand. This adaptable and omnivorous species has proved to be a pest in several of these countries. In Western Australia, which is starling-free, the government pays full-time hunters to patrol the border and shoot starlings as they arrive.

Identification
Starlings are robin-sized birds weighing about 3.2 ounces (90 g). Adults are dark with light speckles on the feathers. The speckles may not show at a distance. The bill of both sexes is yellow during the reproductive cycle (January to June) and dark at other times. Juveniles are pale brown to gray.

Starlings generally are chunky and hump-backed in appearance, with a shape similar to that of a meadowlark. The tail is short, and the wings have a triangular shape when outstretched in flight. Starling flight is direct and swift, not rising and falling like the flight of many blackbirds.

Range
Since their introduction into New York in the 1890s, starlings have spread across the continental United States, northward to Alaska and the southern half of Canada, and southward into northern Mexico. They are native to Eurasia, but have also been introduced in South Africa, Australia, New Zealand, and elsewhere.

Habitat
Starlings are found in a wide variety of habitats including cities, towns, farms, ranches, open woodlands, fields, and lawns. Ideal nesting habitat would include areas with trees or other structures that have cavities suitable for nesting and short grass (turf) areas or grazed pastures for foraging. Ideal winter habitat would include areas with structures and/or tall trees for daytime loafing (resting) and nighttime roosting; and grazed pastures, open water areas, and livestock facilities for foraging.

Food Habits
Starlings consume a variety of foods, including fruits and seeds of both wild and cultivated varieties. Insects, especially Coleoptera and Lepidoptera lawn grubs, and other invertebrates total about one-half of the diet overall, and are especially important during the spring breeding season. Other items including livestock rations and food in garbage become an important food base for wintering starlings.

General Biology, Reproduction, and Behavior
European starlings were brought into the United States from Europe. They were released in New York City in 1890 and 1891 by an individual who wanted to introduce to the United States all of the birds mentioned in Shakespeare’s works. Since that time, they have increased in numbers and spread across the country. They were first observed in Nebraska in 1930, in Colorado in 1939, and in California in 1942. The starling population in the United States is estimated at 140 million birds.

Starlings nest in holes or cavities almost anywhere, including tree cavities, birdhouses, and holes in buildings or cliff faces. Females lay 4 to 7 eggs which hatch after 11 to 13 days of incubation. Young leave the nest when they are about 21 days old. Both parents help build the nest, incubate the eggs, and feed the young. Sometimes 2 clutches of eggs are laid per season, but most of the production is from the first brood fledged.

Although starlings are not always migratory, some will migrate up to several hundred miles, while others may remain in the same general area throughout the year. Hatching-year starlings are more likely to migrate than adults, and they tend to migrate farther.

Outside the breeding season, starlings feed and roost together in flocks. Starling and blackbird flocks often roost together in urban landscape trees or in small dense woodlots or overcrowded tree groves. They choose trees or groves that offer ample perches so that all may roost together. In colder weather they choose dense vegetation such as coniferous trees or structures (such as barns, urban structures) that provide protection from wind and cold. Fall-roosting flocks are relatively small (from several hundred to several thousand birds), but because they are spread over large geographic areas, they can cause widespread nuisance problems. In contrast, winter-roosting flocks are large (sometimes exceeding 1 million birds), but are often confined to a few acres (ha). Some of the winter roosting areas are occupied by starlings year after year. Each day they may fly 15 to 30 or more miles (24 to 48 km) from roosting to feeding sites. During the day when not feeding, they may perch in smaller groups inside farm buildings or in other warm, protected spots in and around urban structures.

Damage and Damage Identification
Starlings are frequently considered pests because of the problems they cause, especially at livestock facilities and near urban roosts. Starlings may selectively eat the high-protein supplements that are often added to livestock rations.

Starlings may also be responsible for transferring disease from one livestock facility to another. This is of particular concern to swine producers. Tests have shown that the transmissible gastroenteritis virus (TGE) can pass through the digestive tract of a starling and be infectious in the starling feces. Researchers, however, have also found healthy swine in lots with infected starlings. This indicates that even infected starlings may not always transmit the disease, especially if starling interaction with pigs is minimized. TGE may also be transmitted on boots or vehicles, by stray animals, or by infected swine added to the herd. Although starlings may be involved in the spread of other livestock diseases, their role in transmission of these diseases is not yet understood.

Starlings cause other damage by consuming cultivated fruits such as grapes, peaches, blueberries, strawberries, figs, apples, and cherries. They were recently found to damage ripening (milk stage) corn, a problem primarily associated with blackbirds. In some areas starlings pull sprouting seeds, particularly winter wheat, and eat the planted seed. Starlings may damage turf on golf courses as they probe for grubs, but the frequency and extent of such damage is not well documented. The growing urbanization of wintering starling flocks seeking warmth and shelter for roosting may have serious consequences. Large roosts that occur in buildings, industrial structures, or, along with blackbird species, in trees near homes are a problem in both rural and urban sites because of health concerns, filth, noise, and odor. In addition, slippery accumulations of droppings pose safety hazards at industrial structures, and the acidity of droppings is corrosive.

Starling and blackbird roosts located near airports pose an aircraft safety hazard because of the potential for birds to be ingested into jet engines, resulting in aircraft damage or loss and, at times, in human injuries. In 1960, an Electra aircraft in Boston collided with a flock of starlings soon after takeoff, resulting in a crash landing and 62 fatalities. Although only about 6% of bird-aircraft strikes are associated with starlings or blackbirds, these species represent a substantial management challenge at airports.

One of the more serious health concerns is the fungal respiratory disease histoplasmosis. The fungus Histoplasma capsulatum may grow in the soils beneath bird roosts, and spores become airborne in dry weather, particularly when the site is disturbed. Although most cases of histoplasmosis are mild or even unnoticed, this disease can, in rare cases, cause blindness and/or death. Individuals who are weakened by other health conditions or who do not have endemic immunity are at greater risk from histoplasmosis.

Starlings also compete with native cavity-nesting birds such as bluebirds, flickers, and other woodpeckers, purple martins, and wood ducks for nest sites. One report showed that, where nest cavities were limited, starlings had severe impacts on local populations of native cavity-nesting species. One author has speculated that competition with starlings may cause shifts in red-bellied woodpecker (Melanerpes carolinus) nesting from urban habitats to rural forested areas where starling competition is less.

Economics of Damage and Control
Consumption of livestock feed by starlings can at times be a substantial economic consideration. Data reported in 1968 from Colorado feedlots estimated the cost of cattle rations consumed during winter by starlings at $84 per 1,000 starlings. Current feed costs and the associated losses would certainly be much higher. A 1967 report indicated that 1 million starlings at a California feedlot resulted in losses of $1,000 per day because of food consumption and contamination, and starling interference with cattle feeding activity. Another report estimated that starlings in Idaho consumed 15 to 20 tons (13.5 to 18 mt) of cattle feed per day. A 1978 study in England estimated that the food eaten by starlings in a calf-rearing unit over three winters was 6% to 12% of the food presented to the calves. Two other studies in England since then found 4% losses and negligible damage, respectively.

Producers who wish to estimate feed losses to starlings at their facilities can do so using one of two methods. The following equation, which was developed from data in Colorado, estimates the cost of feed consumed per day: Cost of feed ration consumed per day = estimated starlings (to the nearest 1,000) x fraction of birds using trough x cost of feed ration per pound (0.4536 kg) x 0.0625 pound (0.02813 kg) consumed per starling per day.

A second method, which may be applicable to most geographic areas, precludes the need of estimating starling populations. It requires the operator to observe the feed troughs several times during the day and estimate the number of starlings entering the troughs per day. From this estimate the cost of the feed ration consumed per day can be estimated with the following equation: Cost of feed ration consumed per day = estimated starling entries into troughs x 0.0033 pounds (0.0015 kg) consumed per starling entry x cost of feed ration per pound (0.4536 kg).

These losses projected over a 3-to 4-month damage season can assist in evaluating the costs and benefits of proposed control measures.

Feed contamination from starling excreta may not be an economic loss for cattle or pig operations. In 2 years of testing at Western Kentucky University, neither pigs nor cattle were adversely affected by long-term exposure to feed heavily contaminated with starling excreta. As compared to controls, no significant differences were observed in weight gain or feed efficiency (ratio of weight gain to weight of feed offered). In addition, there were no observed differences in feed rejection or disease incidence. These results indicate that there is no economic justification for starling control based solely on feed contamination. However, the effects of livestock water contamination from starling excreta have not been well studied.

Starling interference with livestock feeding patterns may have economic importance. A study in England reported that calves in pens protected from starlings showed higher growth rates and better feed conversion than those in unprotected pens. This protection led to an increased profit margin. The difference observed, however, might have been caused by starlings in the unprotrected pens consuming the calf food, especially the high protein portion, rather than by actual interference with the calf feeding.

The costs associated with starlings in the spread of livestock disease may at times be substantial. For example, during the severe winter of 1978-1979, a TGE outbreak occurred in southeast Nebraska, with over 10,000 pigs lost in 1 month in Gage County alone. Starlings were implicated because the TGE outbreak was concurrent with large flocks of starlings feeding at the same facilities. More recent data show that starlings are capable of carrying this disease in their feces. The role of starlings in disease transfer, however, needs further study.

Bird damage to grapes in the United States was estimated to be at least $4.4 million in 1972; starlings were one of the species causing the most damage. Starlings, as well as many other species of birds, also damage ripening cherry crops. A 1972 study in Michigan found 17.4% of a total crop lost to birds. A 1975 study in England estimated damage at 14% (lower branches) to 21% (tree canopy) of the crop; similar 1976 data showed less damage. Starling damage to winter wheat in a study of 218 fields in three regions in Kentucky and Tennessee averaged 3.8%, 0.5%, and 0.4% respectively, with the most serious losses (more than 14%) occurring where wheat was planted late and fields were within 11 miles (16 km) of a large starling roost.

Human health and safety problems associated with urban starling roosts include concerns about the disease histoplasmosis and about aircraft-bird collisions. Although serious problems occur only infrequently, they can have grievous consequences where loss of human life and/or permanent disability may occur. Moreover, equipment repair and replacement costs associated with aircraft-bird collisions can be substantial. For example, the costs of aircraft-bird collisions in the United States are estimated to be at least $20 million per year to commercial aircraft and $10 million per year to Air Force aircraft. These consequences mandate a thorough understanding of urban roost situations and timely roost management where the potential for human health and safety problems exists.

On the beneficial side, starlings eat large quantities of insects and other invertebrates, especially during spring. Many of these invertebrates, such as lawn grubs, are considered to be pests. This benefit, however, is partially offset by the fact that starlings often take over nest cavities of native insect-eating birds. As trends move toward lower pesticide use and sustainable, low-input turf and agricultural systems, the role of starlings and other birds may become more important. Research is needed to further understand potential positive impacts of starlings and to learn how to maximize potential benefits while minimizing problems.

Although starlings are frequently associated with damage problems, some of which clearly cause substantial economic losses, the economics of damage in relation to the cost and effectiveness of controls are not well understood. Several factors contribute to this: (1) Starlings are difficult to monitor because they often move long distances daily from roost to feeding areas, and many migrate. (2) Effectiveness of controls, particularly in relation to the total population in an area, is difficult to document. For example, does population reduction in a particular situation reduce the problem or merely allow an influx of starlings from other areas, and how does this vary seasonally or annually? In addition, does lethal control just substitute for natural mortality or is it additive? (3) The economics of interactions with other species are difficult to measure. For example, how much is a bluebird or flicker worth, and what net benefits occur when starling interference with native cavity-nesting birds is considered? (4) Other factors such as weather and variation among problem situations complicates accurate evaluation of damage and the overall or long-term effectiveness of controls. These points, as well as others mentioned in this chapter, are examples of factors that must be considered in assessing the total economic impact of starlings. Clearly, to minimize starling-human conflicts we need a better understanding of starlings and their interactions with various habitats and control measures.

Legal Status
European starlings are not protected by federal law and in most cases not by state law. Laws vary among states, however, so check with state wildlife officials before beginning a control program. In addition, state or local laws may regulate or prohibit certain control techniques such as shooting or the use of toxicants.


Damage Prevention and Control Methods

Exclusion
Close all openings larger than 1 inch (2.5 cm). Place covering at 45 degree angle on ledges. Porcupine wires on ledges or rafters. Netting to prevent roosting on building beams or to protect fruit crops. PVC or rubber strips to cover door openings; netting where frequent access is not needed.

Cultural Methods and Habitat Modification
Reduce availability of food and water at livestock facilities: remove spilled grain and standing water; use birdproof feeders and storage facilities; feed livestock in open sheds; where appropriate, feed in late afternoon or at night; lower water level in waterers. Modify roost sites by closing buildings; exclude from roost areas with netting (for example, under roof beams); modify specific perch sites. For tree roosts, prune branches of specific trees or thin trees from groves. Frightening
Frightening devices include recorded distress or alarm calls, various sound-producing devices, chemical frightening agents (Avitrol®), lights, and bright objects. Use with fruit crops and starling roosts. Also useful at livestock facilities in warm climates and at facilities located near major roosts.

Repellents
Soft sticky materials (polybutenes) discourage roosting on ledges. Starling repellent is currently under development: methyl anthranilate (grape flavoring). If successful, it may be useful for protecting fruit and as a livestock feed additive.

Toxicants
Starlicide: toxic bait for use around livestock facilities and, in some situations, at roost sites. Toxic perches: can be useful for certain industrial and other structural roost situations.

Fumigants
None are registered.

Trapping
Nest-box traps, for use during nesting season. Decoy traps may be useful around orchards or livestock facilities. Proper care for trap and decoy birds is necessary.

Shooting
Helpful as a dispersal or frightening technique. Not effective in reducing overall starling numbers.



ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (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).


GOT CRITTERS? WE CAN HELP
Wildlife Management Services uses a variety of integrated and ecologically responsible pest management techniques - depending on the circumstances of the problem, the extent of the damage, and public health threats. Call (800) CRITTER for the Wildlife Management Services office nearest you. You can also find an office in your area by using our Office Finder.