The European Starling (Sturnus vulgaris) is a common and widespread bird found in various environments, thriving particularly in areas populated by humans. Their adaptability allows them to utilize a range of habitats, from urban landscapes to agricultural fields, as long as they have access to essential resources for survival and reproduction. Understanding their ecological niche provides insight into their remarkable success as an introduced species.
Habitat Preferences
European Starlings are highly adaptable and commonly inhabit areas around human settlements. They are frequently observed in mowed lawns, city streets, and agricultural fields, which they utilize for foraging. For nesting, they prefer trees, buildings, and other man-made structures that offer suitable cavities or niches. The primary requirements for their habitat include open, grassy areas for foraging, a nearby water source, and ample nesting sites, typically in the form of cavities. While they are widespread, they tend to avoid large, unbroken expanses of dense forest, chaparral, or desert environments.
Diet and Foraging Habits
Starlings exhibit a highly omnivorous diet, consuming almost anything available. However, their diet predominantly consists of insects and other invertebrates, especially when these are readily accessible. Common prey includes grasshoppers, beetles, flies, caterpillars, snails, earthworms, millipedes, and spiders. In addition to invertebrates, they are known to eat a variety of fruits, such as wild and cultivated cherries, holly berries, hackberries, mulberries, tupelo, Virginia creeper, sumac, and blackberries. Their diet also extends to grains, seeds, nectar, livestock feed, and even garbage.
A distinctive foraging behavior of starlings involves probing the ground with their bills. They wander over lawns, fields, and other open areas with short vegetation, poking their closed bills into the ground. Using their strong jaw muscles, they force their bills open to search for soil-dwelling insects and other invertebrates. This method allows them to efficiently access hidden prey.
Nesting Behavior and Reproduction
Nest Site Selection and Construction
Male European Starlings play a key role in nest site selection, often using the chosen site as a means to attract females. Nests are almost exclusively built within cavities, which can be found in buildings, old woodpecker holes, nest boxes, or even in burrows and cliff faces. Nest holes are typically situated between 10 to 25 feet off the ground, though they can be as high as 60 feet.
The nest-building process begins before mating. Males fill the chosen cavity with a mixture of grass, pine needles, feathers, trash, cloth, and string. A depression is formed near the back of the cavity for the nest cup, which is then lined with feathers, fine bark, leaves, and grass. Females often oversee the final arrangements, sometimes removing materials added by the male. Throughout the nesting period, particularly during egg-laying and incubation, starlings actively add fresh green plants to their nests. A nest can be constructed in as little as one to three days.
Reproductive Facts
European Starlings typically lay 3 to 6 eggs per clutch, and they may have one to two broods per year. The eggs are bluish or greenish-white, measuring approximately 1.1 to 1.3 inches in length and 0.8 to 0.9 inches in width. The incubation period lasts for about 12 days, with both the male and female participating. Nestlings remain in the nest for approximately 21 to 23 days. At hatching, the young are helpless, covered in sparse grayish down, and weigh around 6.4 grams. Their eyes remain closed for the first 6 to 7 days of life.
Social Behavior and Aggression
Starlings are highly gregarious birds, often seen foraging in flocks with other species such as grackles, cowbirds, blackbirds, House Sparrows, Rock Pigeons, American Robins, and American Crows. Their social interactions within these flocks can reveal various communication methods.
They signal agitation by flicking their wings or by staring intently at opponents while standing erect, fluffing their feathers, and raising the feathers on their heads. Submissive birds tend to crouch and move away with their feathers sleeked. Confrontations can escalate to birds charging at each other and using their long bills to stab. On perches, birds may push others away by sidling along until the pushed bird runs out of space.
Males attract mates by singing near a claimed nest site and flapping their wings in circles. After pairing, males closely follow their mates to ward off other males. European Starlings are known for their extreme aggression, particularly when competing for desirable nest sites. They have been observed driving away native species, including Wood Ducks, Buffleheads, Northern Flickers, Great Crested Flycatchers, Tree Swallows, and Eastern Bluebirds, from nesting territories.
Conservation Status
Despite their commonality and widespread distribution, the North American population of European Starlings has experienced a decline. According to the North American Breeding Bird Survey, their population has decreased by over 1.2% annually, resulting in a cumulative decline of approximately 50% between 1966 and 2023. Partners in Flight estimates the global breeding population at 250 million and considers them to be of low conservation concern. A 2019 study indicated that the number of European Starlings in the U.S. and Canada was around 93 million.
As a highly successful introduced species, European Starlings are fierce competitors for nesting cavities, often displacing native birds. While this has raised concerns about their impact on native populations, a 2003 study found minimal actual effects on most native cavity-nesting species. Only sapsuckers showed declines directly attributable to competition with European Starlings; other native birds appeared to maintain their populations despite the presence of this introduced species.
References:
- Cabe, Paul R. (1993). European Starling (Sturnus vulgaris), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
- Ehrlich, P. R., D. S. Dobkin, and D. Wheye (1988). The Birder’s Handbook. A Field Guide to the Natural History of North American Birds, Including All Species That Regularly Breed North of Mexico. Simon and Schuster Inc., New York, NY, USA.
- Kalmbach, E. R., and I. N. Gabrielson. (1921). Economic value of the starling in the United States. United States Department of Agriculture Bulletin No. 868, Washington, D.C.
- Koenig, W. D. (2003). European Starlings and their effect on native cavity-nesting birds. Conservation Biology 17:1134–1140.
- Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
- Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
- Rosenberg, K. V., A. M. Dokter, P. J. Blancher, J. R. Sauer, A. C. Smith, P. A. Smith, J. C. Stanton, A. Panjabi, L. Helft, M. Parr and P. P. Marra. Decline of North American Avifauna. Science 366:120-124.
- Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
- Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.
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