BIRDS

European Starling

The first two attempts to introduce the European Starling into North America failed. The third did not, and what has followed since those 60 starlings were released in 1890 in New York City's Central Park has kept ornithologists alternately astounded, puzzled, and infuriated. Much as European human settlers did in the preceding years, the invading birds pushed their way across the continent, taking advantage of its riches and, where necessary, usurping the habitat of residents. What enabled the starling to advance all the way to the Pacific within a mere 60 years? Starlings were not always pests, although, according to historical records, they have associated with people since the advent of agriculture. They were described in detail by Aristotle and Pliny, and the Romans taught them to mimic human speech. The meager mention of starlings by European chroniclers before 1830 is thought to indicate rather limited numbers. After 1830, however, milder European winters eliminated starlings' need to migrate or shortened the migration route, and the conversion of forest into farms created more favorable open habitats and provided cereal grains for food. These concurrent changes are thought to have favored double-brooding, breeding at an earlier age, and formation of ever larger starling colonies (which probably have higher breeding success than small ones) and led to a rapid increase in those populations. Before the turn of the century, the species was brought to our shores. Few people like starlings. But disdain of the species may be tempered by knowledge of its biology. Take, for example, its bill. Unlike most of the 130-member starling family, Sturnidae, the European Starling has jaw muscles that work "backward." Instead of using most of their power to clamp the bill shut, these muscles use it to spring the bill open. Thus the bill functions not just to grip prey but also to pry apart obscuring plants. The closed bill is inserted between blades of grass in thick turf or other cover, and then sprung open to expose hidden prey. As the bill opens, the eyes move forward toward each other, permitting binocular vision. This readily observed foraging technique enables the starling to detect not only active prey but also dormant or stationary prey, as well. William Beecher, who made this discovery during a seven-year study of songbird head musculature and skull adaptations, suggests that this unique hunting maneuver was also key to the high rate of survival of starlings during winter. Consider, as well, starlings' housekeeping. Even more than most cavity nesters, starlings use a wide array of sites and an endless variety of human-built structures. Typically cavity nesters lay their eggs on nothing more than a bed of chips or feathers, but starlings build nests inside their chambers. In addition to gathering dead grasses for those nests, starlings carefully select fresh green vegetation rich in chemicals that act as fumigants against parasites and pathogens. Green sprigs are added to the nest until the eggs hatch. To maintain its insulating properties the nest is kept dry by removing the fecal sacs of the nestlings. Once the chicks are feathered, nest insulation becomes superfluous, the fecal sacs are no longer removed, and fresh anti-parasite greenery is no longer added. Thus, even before fledging, starling nests resemble a pest-ridden compost. But starlings are hardier than many other cavity nesters. They can, for example, withstand the infestation of tens of thousands of mites per nest hole without an increase in mortality. Therefore nest construction includes early (but not late) incorporation of leaves containing fumigants, and minimal, but precisely timed, efforts in nest sanitation, the starling has reduced the energy costs of housekeeping while decreasing the value of its hole for reuse by its competitors.

Starlings are colonial breeders. There are reports of bachelor males feeding the young and, along with the male parent, guarding the nest tree after the fledglings and female parent depart to forage. There may thus be a tendency toward cooperative breeding (which has been found in some tropical members of the starling family) in European Starlings. Observers should be alert for signs of such behavior.

Breeding males may attempt to father a second and even third brood. Their fidelity to mates depends, in part, on the success of the previous brood, but apparently it is not uncommon for males to select a new female for a second brood, perhaps on the basis of her previous success. A family unit usually forages within 200-500 yards of its nest. During nest building and egg laying, unit members make, on average, 30 visits a day to the nest; during incubation this decreases to 18, but when young are being fed, visits jump to 260. Also, visits to the nest may not be restricted to members of a unit. Evidence points to intraspecific nest parasitism -- visiting female starlings are known to dump their eggs in the active nests of other females.

In the winter, starlings become somewhat nomadic but are able to find dormant insects under snow wherever it is not too deep. They show a marked preference for foraging for insects in short grass but are extremely opportunistic and will even rely on fungus to get by in the absence of preferred foods.

Exotic "weeds" often escape the natural controls that limit their numbers at home and may, quite quickly, become pests. Is it possible to control our weed-like starlings? Some think starlings could serve humanity well by ridding pastures of insect infestations, although benefits have been demonstrated under only very special conditions. Nonetheless, a reputation for controlling pests has apparently paved the way for starlings in New Zealand, where nest boxes for them can be found atop many pastureland fence posts. The use of starlings to suppress North American insect outbreaks, however, is unlikely. Instead, programs to control starlings probably will become more common.

Starlings form aggregations with other species which may reach 10 million birds and can be astonishingly difficult to control. Congregations on trees have been discouraged by thinning the canopy. Loudspeakers have been wired throughout vineyards and orchards to broadcast distress calls, which may be effective under some conditions in keeping the birds from roosting. During the past 15 years, where massive winter roosts have occurred, a million or more individuals have been killed at one time by spraying with detergent (which destroys the insulating properties of the plumage). But even these local losses have not put a significant dent in starling populations.

Human modification of North American habitats permitted rapid colonization of the entire continent. Starlings are now ubiquitous, out-competing other such cavity nesters as Eastern Bluebirds, Red-headed Woodpeckers, Northern Flickers, and Great Crested Flycatchers. Within one century, 60 starlings introduced to North America have increased to over 200,000,000 (one-third of the world's European Starling population). How fast and for how long their numbers will continue to grow is uncertain, but it is likely that managing the consequences of their introduction will continue to be difficult, expensive, and (considering the nature of the foe) often unsuccessful.

First brought to North America by Shakespeare enthusiasts in the nineteenth century, European Starlings are now among the continent’s most numerous songbirds. They are stocky black birds with short tails, triangular wings, and long, pointed bills. Though they’re sometimes resented for their abundance and aggressiveness, they’re still dazzling birds when you get a good look. Covered in white spots during winter, they turn dark and glossy in summer. For much of the year, they wheel through the sky and mob lawns in big, noisy flocks.

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 (Fig. 1). 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.

EGGS

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 (Fig. 2). 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 (Fig. 3) 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.

Originally found from:-
http://www.stanford.edu/group/stanfordbirds/text/essays/European_Starlings.html