Starlings

European Starling

Figure 1

Starlings

European starlings (Sturnus vulgaris, Fig. 1) were purposefully introduced from Europe into this country by a small group of people with a passion to introduce all of the animals mentioned in the works of William Shakespeare. After two failed attempts, about sixty European starlings were released into New York's Central Park in 1890 and their descendants have spread across the United States, northward to southern Canada and Alaska, and southward into Central America. There are now an estimated 150 million starlings in the United States alone. Many people dislike the birds because of their aggressive behavior at feeders and nesting sites, and overwhelming flocking and roosting habits.

The European starling is a medium-sized, black songbird with short, triangular wings, speckled plumage, and a short tail. The adult in breeding plumage has a distinctive yellow bill and speckled black with purple-green iridescence. The nonbreeding adult has a black beak and light spots. Juveniles are drab gray-brown overall. Males and females look alike. (Fig. 1)

Facts about Starlings

Food and Feeding Habits

  • Starlings forage on lawns and other areas of short grass, such as pastures, golf courses, parks and similar places.
  • A favorite food is the large larva, or grubs, of the Japanese beetle, which eats the roots of grass plants. (Japanese beetles are not native to the United States and were unintentionally introduced here from Japan in the early 1900s)
  • Starlings have unique jaw muscles designed both to clamp shut and spring open, allowing them to use their bills to pry things apart and make openings in the soil.
  • Starlings also eat seeds and suet at bird feeders, fruit, and food scraps.

Nesting and Roosting Sites

  • Starlings nest in suitable holes and crevices in buildings, utility poles, decaying trees and holes in cliff faces, from six to 60 feet above ground.
  • Males establish territories and choose nest sites, then attract females.
  • Male starlings are very aggressive when claiming nest sites, often taking over nest boxes and other cavities even while native birds as bluebirds, woodpeckers and tree swallows are using them.
  • The nest is an untidy collection of grass, bark strips, twigs, rope and other debris. The nest cup is lined with feathers, moss or other soft material.
  • In late summer and fall, starlings form big flocks and roost in large deciduous trees. When trees lose their leaves, starlings roost in areas that provide protection from wind and cold, including coniferous trees, barns, and the underside of bridges.
  • During the night, individual birds change their position in the roost to minimize energy loss, with older birds maintaining the best positions. (See "Roost Sites" for more information.)
Starling Egg

Figure 2: Photo Credit - Acorn Naturalists

Reproduction

  • Starlings can be building nests, sitting on eggs, or caring for young anytime between mid-February early July.
  • Four to six slightly glossy, pale blue eggs hatch after an incubation period of only 11 to 13 days.
  • Both parents take turns with incubation during the day; at night only the female remains on the nest.
  • The young begin to fly at 18 to 21 days of age, and once they are out of the nest, parents care for them two to four days.
  • The female typically starts laying a second brood shortly after the first set of young fledge. A pair of adults can raise two broods per year in most areas.
  • Starling eggs, which are about the same size, shape, and color as robin eggs, often are found lying on the ground. It is believed that the females drop eggs if they are ready to lay and the nest is not yet complete or has been taken over by another bird.
  • Starlings lay four to six slightly glossy, pale blue eggs. (Fig. 2)

Mortality

  • Adult starlings have few predators, although hawks and falcons occasionally catch them in flight.
  • Young starlings may die from starvation, adverse weather and predation by owls, raccoons, rats, domestic cats and other animals.
  • Humans, via control programs in agricultural areas, are likely responsible for most starling mortality.

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Viewing Starlings

Starlings can be seen almost any time of the year throughout Maine, particularly in areas associated with humans. They are among the few species of birds that tolerate high human density and poorly vegetated landscapes such as industrial sites. Starlings are normally absent only from heavily wooded and alpine areas. They appear to be partially migratory, but patterns vary regionally and individually. Many birds move into urban areas during the winter.

Starlings are often observed walking or running along on lawns, stopping to probe for moth or beetle larvae with their powerful beaks. The short grass makes it easy for them to walk, locate food, and watch for potential predators.

The wings of starlings have a triangular shape when stretched out in flight. Their flight is direct and swift, not rising and falling, like the flight of many other black species.

When starlings spot a perching hawk, falcon, or owl, they will often "mob" the bird, calling loudly, flying around it, and diving toward it. Dense flocks of starlings will also take flight and perform coordinated, complex evasive maneuvers to avoid predators.

During the fall, large, undulating flocks containing hundreds of starlings can be seen flying over towns, water and fields.

Displays

Since starlings are widely distributed and abundant in populated areas, they make great subjects for bird-watchers interested in wildlife behavior.

Wing-Wave Display

Figure 3: Drawing Credit - Stokes

The male performs the wing-wave display when perched; he spreads his wings and rotates them. Both males and females perform fluffing during aggressive encounters. The movement involves facing another bird and puffing out all of its feathers. The other bird may do the same.

The wing-wave display (Fig. 3).

Calls

Starlings use various calls and songs, including whistles, high-pitched squeaks, and imitations of the calls and songs of other birds. Starlings can even imitate the call of a bald eagle and other raptors. (As long ago as the fifth century B.C., the Greeks and Romans kept starlings as caged birds and taught them to imitate human speech.)

Just before pairing in spring and on warm fall days, the male commonly gives a squeal-call near the nest hold when a female flies by.

Roost Sites

Starlings roost on structures or in trees from late summer until the beginning of the breeding season. The number of birds can vary from a hundred to a thousand or more. Roosts are largest in late summer, when composed of newly hatched young, their parents, and non-breeding birds. The roosts become smaller, and may change location, in fall and winter when the adults migrate or return to breeding grounds.

Each sunrise, starlings leave their roost site in small flocks to feed on lawns, cultivated fields, golf courses, wetlands, tidal flats, and debris-rich beaches. Starling will fly thirty miles to a productive feeding site.

Up to two hours before sunset, the starlings farthest from the roost site begin their return trip. The birds travel along the same flight lines day after day. Small flocks join them and the numbers increase as the birds approach the roost site.

Some members will drop out and perch on pre-roosting sites such as trees, power lines, bridges, and towers; the membership of these small groups changes constantly.

Before sunset, all birds leave for the primary roost. There, immense flocks will be swarming, and birds make spectacular dives into the primary roost, flutter about in search of a good perch, and settle down for the night.

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Preventing Conflicts

The starling's long association with humans has strengthened its adaptive characteristics. Because these birds congregate in large numbers and aggressively search out food sources and nest sites in and around buildings, they can come into conflict with people. Here are some suggestions that will help prevent and remedy conflicts that arise.

If starlings nest in buildings: Starlings are adept at establishing nest sites in nooks or crannies in buildings. Nesting activity can damage buildings, create a fire hazard, and cause water damage by clogging gutters and drainpipes.

Prevent starlings from nesting or roosting by installing barriers (Figs. 4, 5) and sealing all potential points of entry. Although starlings have difficulty entering holes smaller than one and a half inch in diameter, house sparrows, bats and other small mammals can slip right in. Use wood, quarter-inch hardware cloth, aluminum flashing, or similar sturdy material. Light material, such as bird netting or rags, will not keep determined starlings out. Replace any loose shingles or siding, and repair broken windows.

Sheet Metal

Figure 4: Drawing Credit - Jenifer Rees

Bird Netting

Figure 5: Drawing Credit - Jenifer Rees

Install commercially available vent guards to prevent starlings from entering exhaust vents and dryer vents. If necessary, cover the ends of elevated drainpipes with quarter-inch hardware cloth during the nesting season. All screening should be checked periodically to make sure it isn't clogged.

Starlings can be prevented from roosting on a building ledge by securing sheet metal, wood, Styrofoam blocks, or other materials at a 60-degree angle. (Fig. 4)

The undersides of rafters can be covered with bird netting to prevent starlings from gaining access to roosting spots. (Fig. 5)

Prevent starlings from roosting on walls covered with vegetation by removing the vegetation or draping bird netting over the area. In new construction, avoid creating small cavities or spaces with access from the exterior into which starlings can enter and nest.

Starlings can be evicted from buildings and other sites any time of year. State and federal laws do not protect this species. A stick can be used to remove nests. The nesting material should be collected and removed to prevent the birds from using it for a new nest. Take immediate steps to prevent starlings from rebuilding.

If the birds are caring for young, one approach is to wait until the young can fly out of the nest, then remove all nesting materials and cover all openings.

Feeder

Figure 6: Drawing Credit - Jenifer Rees

String

Figure 7: Drawing Credit LFWITPN

Cage

Figure 8: Drawing Credit - Jenifer Rees

If starlings use feeders: Starlings are attracted to both seed and suet feeders, and their aggressive habits can deplete food supplies and keep smaller birds from approaching. You can discourage starlings by choosing the right bird feed and style of feeder, or by modifying an existing feeder.

Because starlings have difficulty cracking the commercially available black sunflower seeds, over this food in feeders.

Starlings have difficulty landing on a small perch, so shorten perches or remove them altogether. (Fig. 6) Most songbirds do not need a perch to access the seed.

To reduce waste, prevent crowding at the feeder, and keep starlings away, remove all perches and cover all but one lower feeding port with duct tape or electrician's tape. (Fig. 6)

You can also use a small feeder that swings and twirls whenever a heavy bird (like a starling) lands on it. (Fig. 7)

Starlings cannot land on a hanging pine cone stuffed with peanut butter or suet. Smaller birds have no trouble landing and feeding. (Fig. 7)

Because starlings have trouble clinging upside down, use a suet feeder that requires birds to clasp the feeder from below. Consult a bird specialty store or the Internet to find feeders designed to deter this species.

Wire placed over a platform feeder to allow small birds in and keep large birds out. (Fig. 8)

Before Prunning

Figure 9a: Drawing Credit Jenifer Rees

After Prunning

Figure 9b: Drawing Credit Jenifer Rees

If starlings roost in trees: In fall and winter, the communal night roosts of thousands of starlings create accumulations of droppings below the roost. When a health official deems this a health risk to the public, steps need to be taken to disperse the flock. Options include installing visual and auditory scare devices, and thinning 30 to 50 percent of the branches of roost trees (or removing trees from dense groves) to reduce the availability of perch sites and to open the trees to the weather. (Fig. 9) A tree service company can perform this work. Experience has shown that the best results occur when the pruning of trees is combined with scare tactics. (See Canada Geese for information on visual, auditory, and other scare devices)

Before and after pruning of a coniferous tree to reduce its attractiveness to roosting starlings. (Fig. 9)

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Protecting Native Cavity Nesters from Starlings

Although starlings can be interesting to watch in highly built-up areas where few other bird species thrive, they can be a serious problem when they compete with native cavity-nesting birds for nesting spots. Cavity nests are becoming increasingly less plentiful as trees are cut down.

Male starlings are especially aggressive in their search for nest sites. They will peck holes in eggs laid by other birds, throw out their nesting material, and kill their young. Starlings will build nests on top of existing nests containing eggs, and can even evict the much larger wood duck from its nest box.

Bird House

Figure 10: Drawing Credit - LFWITPN

To prevent problems:

  • Don't attract starlings. (Follow recommendations under "Preventing Conflicts".)
  • Install nest boxes designed to exclude starlings (Fig. 10). Many native songbirds can use an entry hole smaller than the inch and a half that starlings need. (Table 1). Be alert to hole enlargement by flickers and rodents, and replace or add a new front with the proper hole size. To reduce the size of a door, attach a piece of wood over the door and drill the appropriate sized hole, then file down all rough edges. Or, buy a pre-drilled metal plate and attach it over the existing entry.
  • A nest box designed to provide a safe site for native cavity-nesting songbirds. (Fig. 10)
  • Do not install nest boxes that have perches. Starlings need perches but native species do not.
  • When you see a starling building in a nest box, repeatedly remove the nesting material or plug the entry hole for a few days or longer. Carefully monitor the box throughout the breeding season for use by starlings.
  • If starlings have laid eggs in a nest box, vigorously shake the eggs and return them to the nest. The adults will incubate them, but the eggs will not hatch. Because state and federal laws don't protect these birds, it is legal to remove their nests and destroy the eggs or the birds themselves.
  • Clean out nest boxes each year. If birds build on top of old nests, the new nest may be close enough to the entry hold so that starlings or other predators can pull out the occupants.
  • If you have just a couple of boxes, take them down each year or block the entrance holes after the breeding season. Remount them or open the entrance only when you see or hear native species the following spring. Keep in mind that because starlings do not migrate for the winter, they will be looking for nesting sites long before the migrants return.

Table 1. Entry hole needs of some small native cavity-nesting birds

Species
Diameter of entrance
Chickadees
1 inch., more or less*
Tree swallow
1¼ inch
House wren
1 1/8 inch
Nuthatch
1 inch*
Eastern bluebird
1¼ inch*
Hairy woodpecker
1½ inch
Downy woodpecker
1 inch, more or less

* This species will also use the diamond-shaped entry hole shown in Figure 5.

Netting

Figure 11: Drawing Credit - Jenifer Rees

If starlings eat fruits and vegetables: A small flock of starlings can quickly ruin or remove a fruit or young vegetable crop. Protect fruit crops with flexible bird netting, which can be purchased in a variety of lengths and widths at garden and hardware stores; professional quality materials and hardware are available from bird-control companies and over the Internet. Secure the base of the shrub or the tree to prevent starlings from gaining access from below. (Fig. 9) Individual small branches containing fruit can be protected with an onion sack or similar mesh covering.

Protect fruit crops with flexible bird netting. Secure the netting at the base of the shrub or tree to prevent access from below. (Fig. 11)

Row crops, such as strawberries, can be completely covered during the fruiting season. If the netting is to be used for several harvest seasons, it may be worth the extra effort to construct a frame to support the netting.

Scare devices, such as pie tins and commercially available Mylar balloons or Mylar scare tape, are known to provide temporary protection. Suspend balloons at least three feet above trees or bushes, or from lines between posts. Use tethers at least three feet long.

Attach special red and silver bird-scare tape to stakes and stretch it 18 inches above the areas that need protection. Twist the tape several times before attaching it to stakes so that the visible interval of red/silver is 16 inches. The tape should move freely, so that when a slight breeze blows it will flash in the sun. The space between tapes will have to be no more than five feet to be effective.

Because most birds will fly into a strawberry patch, land on the ground between the plants and eat the ripe strawberries from there, scare devices placed above the patch are not effective. Instead, place the scare tape between the rows. The tape should sag slightly but should not be less than three inches or more than five inches from the ground. Move scare devices weekly (daily if possible) so birds do not become accustomed to them; these tactics are most successful if you put them in place before birds become a problem.

Always harvest ripe fruit immediately.

Protect germinating corn plants and other crops with bird netting until plants are about eight inches tall.

In areas with lots of air movement, attach large plastic trash bags to wooded stakes six or seven feet high; add other visual scare devices as needed.

Cracker shells and propane cannons may be needed in larger plantings. Ultrasonic devices are not effective at frightening starlings.

Other Control Techniques

Trapping: Research has shown that intensive trapping and euthanizing can temporarily reduce starling numbers and damage. This may be worthwhile in some situations, such as at a winter cattle-feeding operation or at airports. However, it has no effect on the number of starlings returning the next year unless it is done repeatedly and when more than fifty percent of the population is removed each time.

Small-scale traps are available from enterprises over the Internet. Check the trap every two hours for non-targeted birds.

Do not trap starlings and release them elsewhere. The birds can easily return – or, they can cause problems in the new area. If you cannot humanely kill them yourself, find a falconer or wildlife rehabilitation center that will accept live starlings to feed to birds of prey.

Shooting: Shooting is not an effective way to manage starling populations overall. The number of birds that can be killed by shooting is small relative to the size of the flock. However, shooting may be helpful where only a few birds are present, or to supplement or reinforce other dispersal techniques. First become familiar with state laws dealing with discharging a firearm near a dwelling and, if you are in an urban area, local ordinances regarding discharging a firearm.

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Public Health Concerns

Although health risks from birds are often exaggerated, a large population of roosting starlings can be of concern. The most serious risk is from disease organisms that can grow in accumulations of starling droppings, feathers, and debris under a roost, particularly if the roost has been active for years. If you live or work near a large concentration of starling droppings, contact the Department of Health for recommended precautions.

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Legal Status

Starlings are not covered in the Migratory Bird Treaty Act (MBTA) of 1918, which was passed for the protection of native migratory birds in North America. Starling nests and eggs may be removed or destroyed at any time. A hunting license is not required to take, possess or destroy the nest or eggs of starlings.

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Additional Information

Books

New England Wildlife, Habitat, Natural History, and Distribution
Written by: Richard DeGraff, and Mariko Yamasaki
University Press of New England, 2001.
(Available from: www.upne.com)

Internet Resources

Adapted from: "Living with Wildlife in the Pacific Northwest"
(see Washington Department of Fish and Wildlife)

Written by: Russell Link, Wildlife Biologist, Email Russell Link, with assistance from WDFW Biologists Rich Beausoleil and Rocky Spencer

Design and layout: Peggy Ushakoff, ITT2

Illustrations: As credited

Copyright 2007 by the Washington Department of Fish and Wildlife


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