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Potentially Misidentified Species:
The physical characteristic noted above should be sufficient to identify S.
vulgaris by sight. The species is noted to be an accomplished mimic,
however, and misidentification of the vocalizations of this species is
therefore possible (Chow 2000).
II. HABITAT AND DISTRIBUTION
Regional Occurrence:
Introduced to North America in 1890, S. vulgaris now occur throughout
most of the continent. The greatest densities in the U.S. occur in the Midwest
and Mid-Atlantic states, but the species can also be found throughout Florida.
IRL Distribution:
S. vulgaris is established throughout the state, including the 6
counties of the IRL watershed.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Adult European starlings re ach a length of 21.5 cm and a weight of 70-100 g. They are long-lived; one wild individual is documented to have lived
more than 15 years and banding studies have shown individuals may live up to 21
years (Chow 2000, CWBO 2004).
Abundance:
S. vulgaris is one of the world's most abundant birds (Kahane 1988;
Craig and Feare 1999).The 1994 U.S. S. vulgaris population was estimated
at 140 million birds and the expanding population is likely now to be
substantially larger. Migrating flocks may consist of up to 3,000 individuals
(Chow, Kern 2001).
In the late spring through late summer, starlings are commonly encountered in
Florida as dispersed pairs. In the fall and winter, they aggregate as large
migrating flocks, although a year-round Florida population exists as well (Chow
200, Kern 2001).
Reproduction:
Reproduction is sexual and oviparous. The breeding season generally persists
from late spring through mid-summer. In the northern hemisphere thi eseason
typically occurs from late March and to early July and in the southern
hemisphere from September through December.
Clutch sizes average 4-6 eggs and females may produce up 3 clutches over the
course of a breeding season. The species is polygynous, with males breeding
with multiple females (Kahane 1988, Craig and Feare 1999, Kern 2001).
Embryology:
Nest incubation lasts from 11-15 days. Nesting duties are shared between males
and females, but females possess a more prominent incubation patch (a
defeathered abdominal area with thickened skin and a rich blood vessel bed) and
incubate the eggs for the majority of time.
Hatchlings are helpless at birth and feeding and nestkeeping chores are shared
by both parents. Male parental care is minimal for clutches they may sire late
in the season. Young are fed only soft animal fird initially, and over time
the diet expands to include a vider variety of animal and plant material.
Young remain in the nest for 21-23 days and may rely on parents to feed them
for a few days beyond this. Young birds leave the nest to form flocks with
other young birds (Kahane 1988, Craig and Feare 1999, Chow 2000, CWBO 2004).
IV. PHYSICAL TOLERANCES
Temperature:
At environmental temperatures between 15-40°C S. vulgaris can maintain
its body temperature without energetic expenditure. They can survive at lower
temperatures by expending energy to produce body heat (Collins 2007).
V. COMMUNITY ECOLOGY
Trophic Mode:
S. vulgaris is an omnivorous species with a broad generalist diet. The
diet consists mainly of seeds, insects, invertebrates, fruits and other plant
material (Chow 2000).
Associated Species:
In addition to forming large monotypic flocks, Kern (2001) notes European
starlings may form multi-species flocks with a variety of species including
blackbirds (Turdus spp.), common grackles (Quiscalus quiscula),
and cowbirds (Molothrus spp.).
VI. INVASION INFORMATION
Invasion History:
Native to Eurasia and North Africa, Sturnus vulgaris was intentionally
introduced to North America in 1890-1891. Accounts reveal that a New York
industrialist inspired by the portrayal of the bird in the plays of William
Shakespeare released 100 individuals in Central Park, although several other
attempts at introduction were also made (Chapman 1966). The birds introduced
to New York rapidly multiplied and expanded their introduced range. The
species was first reported from Florida in 1918, less than 30 years after the
initial introduction, and the first report of nesting activity in Florida dates
to Pensacola, 1932. By 1949, Sturnus vulgaris nesting had expanded to
Orlando (Sprunt 1954, GSMFC).
In the U.S. the species is considered to be established and expanding, and
eradication is not considered to be a plausible form of management (ISSG). High fecundity, polygynous reproductive behavior, and broad generalist
dietary and habitat requirements facilitate the ability of S. vulgaris
to rapidly multiply and invade new areas (Craig and Feare 1999; Kahane 1988).
Potential to Compete With Natives:
European starlings are aggressive competitors capable of displacing native
populations. The generalist feeding habits and efficiency at foraging for
invertebrates as well as seeds and fruits suggests Sturnus vulgaris are
likely to come into direct competition with a wide range of co-occurring birds.
Airola and Grantham (2003) report a correlation between the decline in the
number of urban nesting purple martens (Progne subis) and an increase in
the number of co-occurring Sturnus vulgaris. There is widespread
concern that overpopulation by Sturnus vulgaris is capable of reducing
avian diversity (Chow 2000).
Possible Economic Consequences of Invasion:
Although Sturnus vulgaris is an important consumer of crop-damaging
insects, the net economic effect of this introduced species is negative. The
primary impact of Sturnus vulgaris is related to the agricultural crop
damage the species causes. Large migrating flocks can inflict massive damage
to fruit and grain crops. Starlings also harbor a number of diseases that pose
serious health risks for human populations, including blastomycosis, beef
measles, and histoplasmosis. Additionally, they are a nuisance species that
poses an airstrip hazard, and can damage roof linings amd other man-made
structures (Weber 1979, Kahane 1988, Craig and Feare 1999, Chow 2000,
Adeney 2001).
Sturnus vulgaris is listed by ISSG as as among "100 of the Worst" global
invasive organisms.
VII.
REFERENCES
Adeney J.M. 2001. Introduced Species Summary Project: European Starling
(Sturnus vulgaris). Available online.
Chapman F.M. 1966. Handbook Of Birds Of Eastern North America. Dover
Publications, Inc. New York. 581 p.
Chow, J. 2000. Sturnus vulgarisi, Animal Diversity Web. Available online.
Craig, A. and C. Feare. 1999. The Starling. Princeton University Press, New Jersey. 285 p.
Press.
Kahane, D. 1988. The Invasion of California by the European Starling (Sturnus vulgaris). Unpublished Masters' Thesis, University of California. 133 p.
Press.
Kern, William J. 2004. European Starling. (UF/IFAS) SSWEC-118. 7 p.
Weber, W. J., 1979. Health hazards from pigeons, starlings and English
sparrows: Diseases and parasites associated with pigeons, domestic animals,
includes suggestions for bird control. Thomson Publications, New York. 138 p.
Report by:
J. Masterson, Smithsonian Marine Station
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Page last updated: August 31, 2007 |
