''Sturnus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

starlings Starlings are small to medium-sized passerine (perching) birds known for the often dark, glossy iridescent sheen of their plumage; their complex vocalizations including mimicking; and their distinctive, often elaborate swarming behavior, known ...

. As discussed below, the

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

of this group is complex, and other authorities differ considerably in which

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

they place in this genus, and in the species boundaries within ''Sturnus''. The genus name ''Sturnus'' is

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "starling". This genus has representatives across most of

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

and one species, the

common Common may refer to: As an Irish surname, it is anglicised from Irish Gaelic surname Ó Comáin. Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common, a central public park in Boston, Massachusetts * Cambridge Com ...

or European starling, has been introduced to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. The more northerly breeding species are completely or partially migratory, wintering in warmer regions. The ''Sturnus'' starlings are terrestrial species; they walk rather than hop, and have modifications to the skull and its muscles for open-bill probing. The latter adaptation has facilitated the spread of this genus from humid tropical southern

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

to cooler regions of

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and Asia. Starlings nest in holes in trees or buildings. They are

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

and mostly feed on the ground; they specialise in taking

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s from just below the surface. This is facilitated by the head adaptations mentioned above, which enable the birds to probe with the bill open, closing it to secure prey items. The plumages within this group are variable, but all the species have the starling's familiar triangular wing shape. They are capable of imitating many sounds and they have been recorded mimicking sounds such as that of a squeaky door.

Taxonomy and systematics

The

''Sturnus'' was introduced in 1758 by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the

tenth edition Tenth may refer to: Numbers * 10th, the ordinal form of the number ten * One tenth, , or 0.1, a fraction, one part of a unit divided equally into ten parts. ** the SI prefix deci- ** tithe, a one-tenth part of something * 1/10 of any unit of me ...

of his ''

Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...

''. The genus name ''Sturnus'' is

for "starling". Of the four species included by Linnaeus, the

common starling The common starling (''Sturnus vulgaris''), also known simply as the starling in Great Britain and Ireland, and as European starling in North America, is a medium-sized passerine bird in the starling family, Sturnidae. It is about long and ha ...

(''Sturnus vulgaris'') is considered the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. The common and

spotless starling The spotless starling (''Sturnus unicolor'') is a passerine bird in the starling family, Sturnidae. It is closely related to the common starling (''S. vulgaris''), but has a much more restricted range, confined to the Iberian Peninsula, Northwest ...

s are particularly closely related, and interbreed to some extent where their ranges overlap in southwestern

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and northeastern

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

. The non-migratory spotless starling may be descended from a population of ancestral ''S. vulgaris'' that survived in an

Iberian Iberian refers to Iberia. Most commonly Iberian refers to: *Someone or something originating in the Iberian Peninsula, namely from Spain, Portugal, Gibraltar and Andorra. The term ''Iberian'' is also used to refer to anything pertaining to the fo ...

refugium during an

Ice Age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

retreat.

Species

Two extant

are recognized:

Mating system

mating system A mating system is a way in which a group is structured in relation to sexual behaviour. The precise meaning depends upon the context. With respect to animals, the term describes which males and females mating, mate under which circumstances. Reco ...

is much more than just reproduction. It includes all the benefits and costs that the female weighs when choosing a mate and the competition that males, and sometimes females, go through when trying to win a mate. The genus ''Sturnus'' uses three major mechanisms in their complex mating system:

parental care Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal k ...

, differential allocation, and (arguably) the

sexy son hypothesis The sexy son hypothesis in evolutionary biology and sexual selection, proposed by Patrick J. Weatherhead and Raleigh J. Robertson of Queen's University in Kingston, Ontario in 1979, states that a female's ideal mate choice among potential mates ...

Parental care

Male '' Sturnus unicolor'' individuals face a choice when it comes to the mating season. They can either invest in parental care, through helping feed the young, provide shelter, etc. and be monogynous or they can control many nests at one time, increase the number of matings they engage in and be

polygynous Polygyny () is a form of polygamy entailing the marriage of a man to several women. The term polygyny is from Neoclassical Greek πολυγυνία (); . Incidence Polygyny is more widespread in Africa than in any other continent. Some scholar ...

. To add to this, much of the time their choice is biological. ''Sturnus unicolor'' males are more likely to be polygynous and be less involved in parental care if they have higher levels of testosterone. In addition, females of the ''

Sturnus vulgaris The common starling (''Sturnus vulgaris''), also known simply as the starling in Great Britain and Ireland, and as European starling in North America, is a medium-sized passerine bird in the starling family, Sturnidae. It is about long and ha ...

'' species see a decrease in their fitness if the male is polygynous because there is no assistance in nestling feeding. Offspring success per nest, however, is significantly higher if there is parental care from the male, but males see greater overall fitness when they are polygynous. This is the trade off and the cost/benefit balance that each individual must go through.

Differential allocation

To try and make the male stay faithful to her, a female will act aggressively towards another female that solicits his attention. If the male looks like he is going to leave, she will perform aggressive acts towards a prospecting female, in an attempt to have the male stay. Males respond to this behaviour, and the resident female's aggressive acts towards prospecting females do play a role in whether the male stays

monogamous Monogamy ( ) is a relationship of two individuals in which they form a mutual and exclusive intimate partnership. Having only one partner at any one time, whether for life or serial monogamy, contrasts with various forms of non-monogamy (e.g. ...

. The female then responds to whether or not the male sticks around to invest in parental care. If the father stays monogamous, she will allocate more maternal steroid hormones to the eggs she lays later. Doing so negates the effects of hatching asynchrony. When the female is alone, she has difficulty finding enough resources to fully take care of all the offspring. Therefore, if the male is monogamous, she allows all the young to hatch at a similar time, and at a similar nutritional state. If the male is not around, she will allow asynchronous hatching and even allow a

brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American periodical cicadas: ** Brood X, the largest br ...

reduction if she cannot take care of all the young. This allocation of resources to the more desirable situation is differential allocation.

Sexy son hypothesis

The

is an attempt to explain why a female may choose to mate with a previously mated (polygynous) male. This hypothesis suggests that the female mates with a polygynous male because he has already proven himself successful and will therefore be likely to pass these successful

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

s to his sons. Although it may not be ideal for the female at the time, her genes are likely to get passed on for many generations due to her sons' success. Those sons are likely to exhibit many of the behavioral qualities of the father, causing them to also be highly successful in their sexual maturity. This hypothesis has its critics, however. One counter-argument is that a female who chooses a polygynous mate, for a chance that her sons grow up to be successful and pass her genes on, would be risking her own health. The hypothesis has been shown to be flawed in some scenarios. A female that mates with a previously mated male, who is also likely to leave ''her'' nest, fledges far fewer young than one that mates with a monogynous male.

Former species

Formerly, some authorities also considered the following species (or subspecies) as species within the genus ''Sturnus'': *

Straw-headed bulbul The straw-headed bulbul (''Pycnonotus zeylanicus'') is a species of songbird in the bulbul family, Pycnonotidae. It is found from the Malay Peninsula to Borneo. Its natural habitats are subtropical or tropical moist lowland forest, subtropical or ...

(as ''Sturnus zeylanicus'')

References

External links

* {{Authority control Bird genera Taxa named by Carl Linnaeus