House sparrow - WikiHQ

thumb|An audio recording of a house sparrow

The house sparrow (Passer domesticus) is a bird of the sparrow family Passeridae, found in most parts of the world. It is a small bird that has a typical length of and a mass of . Females and young birds are coloured pale brown and grey, and males have brighter black, white, and brown markings. One of about 25 species in the genus Passer, the house sparrow is native to most of Europe, the Mediterranean Basin, and a large part of Asia. Its intentional or accidental introductions to many regions, including parts of Australasia, Africa, and the Americas, make it the most widely distributed wild bird.

The house sparrow is strongly associated with human habitation, and can live in urban or rural settings. Though found in widely varied habitats and climates, it typically avoids extensive woodlands, grasslands, polar regions, and hot, dry deserts far away from human development. For sustenance, the house sparrow routinely feeds at home and public bird feeding stations, but naturally feeds on the seeds of grains, flowering plants and weeds. However, it is an opportunistic, omnivorous eater, and commonly catches invertebrates such as insects and their larvae, caterpillars, and many other natural foods.

Because of its numbers, ubiquity, and association with human settlements, the house sparrow is culturally prominent. It is extensively, and usually unsuccessfully, persecuted as an agricultural pest. It has also often been kept as a pet, as well as being a food item and a symbol of lust, sexual potency, commonness, and vulgarity. Though it is widespread and abundant, its numbers have declined in some areas. The bird's conservation status is listed as least concern on the IUCN Red List.

Description

Measurements and shape

The house sparrow is typically about long, ranging from . The house sparrow is a compact bird with a full chest and a large, rounded head. Its bill is stout and conical with a culmen length of , strongly built as an adaptation for eating seeds. Its tail is short, at long. The wing chord is , and the tarsus is . Wingspan ranges from .

Plumage

The plumage of the house sparrow is mostly different shades of grey and brown. The sexes exhibit strong dimorphism: the female is mostly buffish above and below, while the male has boldly coloured head markings, a reddish back, and grey underparts. The Latin word domesticus means "belonging to the house", like the common name a reference to its association with humans. The house sparrow is also called by a number of alternative English names, including English sparrow, chiefly in North America; and Indian sparrow or Indian house sparrow, for the birds of the Indian subcontinent and Central Asia. Dialectal names include sparr, sparrer, spadger, spadgick, and philip, mainly in southern England; spug and spuggy, mainly in northern England; spur and sprig, mainly in Scotland; and spatzie or spotsie, from the German ', in North America.

Taxonomy

thumb|right|A pair of [[Italian sparrows, in Rome]]

The genus Passer contains about 25 species, depending on the authority, 26 according to the Handbook of the Birds of the World. Most Passer species are dull-coloured birds with short, square tails and stubby, conical beaks, between long.

The taxonomy of the house sparrow and its Mediterranean relatives is complicated. The common type of "willow sparrow" is the Spanish sparrow, which resembles the house sparrow in many respects. It frequently prefers wetter habitats than the house sparrow, and it is often colonial and nomadic. In most of the Mediterranean, one or both species occur, with some degree of hybridisation. In North Africa, the two species hybridise extensively, forming highly variable mixed populations with a full range of characters from pure house sparrows to pure Spanish sparrows.

In most of Italy, the breeding species is the Italian sparrow, which has an appearance intermediate between those of the house and Spanish sparrows. Its specific status and origin are the subject of much debate, but it may be a case of long-ago hybrid speciation.

Migratory birds of the subspecies P. d. bactrianus in the P. d. indicus group were recorded overlapping with P. d. domesticus birds without hybridising in the 1970s, so the Soviet scientists Edward I. Gavrilov and M. N. Korelov proposed the separation of the P. d. indicus group as a separate species. However, P. d. indicus group and P. d. domesticus group birds intergrade in a large part of Iran, so this split is rarely recognised. This variation follows predictable patterns, with birds at higher latitudes being larger and darker and those in arid areas being smaller and paler. However, how much this is caused by evolution or by environment is not clear. Similar observations have been made in New Zealand and in South Africa. The introduced house sparrow populations may be distinct enough to merit subspecies status, especially in North America and southern Africa,

P. d. rufidorsalis <small>C. L. Brehm, 1855</small>, described from Khartoum, Sudan, is found in the Nile valley from Wadi Halfa south to Renk in northern South Sudan, and in eastern Sudan, northern Ethiopia to the Red Sea coast in Eritrea. Central America, southern South America, southern Africa, part of West Africa, Australia, New Zealand, and islands throughout the world. It has greatly extended its range in northern Eurasia since the 1850s, and continues to do so, as was shown by its colonisation around 1990 of Iceland and Rishiri Island, Japan. The extent of its range makes it the most widely distributed wild bird on the planet.

Introduction

The house sparrow has become highly successful in most parts of the world where it has been introduced. This is mostly due to its early adaptation to living with humans, and its adaptability to a wide range of conditions. Other factors may include its ability to suppress costly inflammatory and behavioural responses to immune challenges in its non-native range, compared to less-successful invaders like the Eurasian tree sparrow. Where introduced, it can extend its range quickly, sometimes at a rate over per year. In many parts of the world, it has been characterised as a pest, and poses a threat to native birds. A few introductions have died out or been of limited success, such as those to Greenland, the Bahamas, and Cape Verde. intended to control the ravages of the linden moth. In North America, the house sparrow now occurs from the Northwest Territories of Canada to southern Panama,

The house sparrow was first introduced to Australia in 1863 at Melbourne and is common throughout the eastern part of the continent as far north as Cape York, where every house sparrow found in the state is killed. House sparrows were introduced in New Zealand in 1859, and from there reached many of the Pacific islands, including Hawaii.

In southern Africa, birds of both the European subspecies (P. d. domesticus) and the Indian subspecies (P. d. indicus) were introduced around 1900. Separate introductions of house sparrows have occurred several other parts of Africa, including Kenya, where it is thought that sparrows were introduced to Mombasa around 1950.

In South America, it was first introduced near Buenos Aires around 1870, and quickly became common in most of the southern part of the continent. The only terrestrial habitats that the house sparrow does not inhabit are dense forest and tundra. Well adapted to living around humans, it frequently lives and even breeds indoors, especially in factories, warehouses, and zoos. It has been recorded breeding in an English coal mine below ground, and feeding on the Empire State Building's observation deck at night. It reaches its greatest densities in urban centres, but its reproductive success is greater in suburbs, where insects are more abundant. and an ability to survive without water by ingesting berries. Where these two species overlap, the house sparrow is usually more common than the Eurasian tree sparrow, but one species may replace the other in a manner that ornithologist Maud Doria Haviland described as "random, or even capricious". In most of its range, the house sparrow is extremely common, despite some declines, The house sparrow feeds mostly on the ground, but it flocks in trees and bushes. At feeding stations and nests, female house sparrows are dominant despite their smaller size, and they can fight over males in the breeding season.

House sparrows also have strong social learning ability, for example about novel objects in their environments. Typically, house sparrows show a lot of variation in their responses to novel objects, foods, and environments, where some individual birds are willing to approach and explore novel items, whereas others stay away, a behaviour known as "neophobia." Captive house sparrows learned about novel objects near their food dish (and changed their behaviour towards novel objects) both from observing another individual and from hearing recorded sparrow calls.

Sleep and roosting

thumb|An immature house sparrow sleeping

House sparrows sleep with the bill tucked underneath the scapular feathers. Outside of the reproductive season, they often roost communally in trees or shrubs. Much communal chirping occurs before and after the birds settle in the roost in the evening, as well as before the birds leave the roost in the morning. Some congregating sites separate from the roost may be visited by the birds prior to settling in for the night. Head scratching is done with the leg over the drooped wing. and nectar robbing kowhai flowers. In common with many other birds, the house sparrow requires grit to digest the harder items in its diet. Grit can be either stone, often grains of masonry, or the shells of eggs or snails; oblong and rough grains are preferred.

Several studies of the house sparrow in temperate agricultural areas have found the proportion of seeds in its diet to be about 90%. It will eat almost any seeds, but where it has a choice, it prefers cereals: oats, wheat or maize. Rural birds tend to eat more waste seed from animal dung and seed from fields while urban birds tend to eat more commercial bird seed and weed seed. In urban areas, the house sparrow also feeds largely on food provided directly or indirectly by humans, such as bread, though it prefers raw seeds. The house sparrow also eats some plant matter besides seeds, including buds, berries, and fruits such as grapes and cherries. In temperate areas, the house sparrow has an unusual habit of tearing flowers, especially yellow ones, in the spring.

Animals form another important part of the house sparrow's diet, chiefly insects, of which beetles, caterpillars, dipteran flies, and aphids are especially important. Various noninsect arthropods are eaten, as are molluscs and crustaceans where available, earthworms, and even vertebrates such as lizards and frogs. Young house sparrows are fed mostly on insects until about 15 days after hatching. They are also given small quantities of seeds, spiders, and grit. In most places, grasshoppers and crickets are the most abundant foods of nestlings. True bugs, ants, sawflies, and beetles are also important, but house sparrows take advantage of whatever foods are abundant to feed their young. House sparrows have been observed stealing prey from other birds, including American robins.

Locomotion

The house sparrow's flight is direct (not undulating) and flapping, averaging and about 15 wingbeats per second. On the ground, the house sparrow typically hops rather than walks. It can swim when pressed to do so by pursuit from predators. Captive birds have been recorded diving and swimming short distances under water. Two subspecies, P. d. bactrianus and P. d. parkini, are predominantly migratory. Unlike the birds in sedentary populations that migrate, birds of migratory subspecies prepare for migration by putting on weight.

Breeding

thumb|A pair of the Indian subspecies (P. d. indicus) mating in [[Kolkata]]

House sparrows can breed in the breeding season immediately following their hatching, and sometimes attempt to do so. Some birds breeding for the first time in tropical areas are only a few months old and still have juvenile plumage. Birds breeding for the first time are rarely successful in raising young, and reproductive success increases with age, as older birds breed earlier in the breeding season, and fledge more young. As the breeding season approaches, hormone releases trigger enormous increases in the size of the sexual organs and changes in day length lead males to start calling by nesting sites. The timing of mating and egg-laying varies geographically, and between specific locations and years because a sufficient supply of insects is needed for egg formation and feeding nestlings.

Males take up nesting sites before the breeding season, by frequently calling beside them. Unmated males start nest construction and call particularly frequently to attract females. When a female approaches a male during this period, the male displays by moving up and down while drooping and shivering his wings, pushing up his head, raising and spreading his tail, and showing his bib. Males may try to mate with females while calling or displaying. In response, a female will adopt a threatening posture and attack a male before flying away, pursued by the male. The male displays in front of her, attracting other males, which also pursue and display to the female. This group display usually does not immediately result in copulations. Other males usually do not copulate with the female. Copulation is typically initiated by the female giving a soft dee-dee-dee call to the male. Birds of a pair copulate frequently until the female is laying eggs, and the male mounts the female repeatedly each time a pair mates.

The house sparrow is monogamous, and typically mates for life, but birds from pairs often engage in extra-pair copulations, so about 15% of house sparrow fledglings are unrelated to their mother's mate. Males guard their mates carefully to avoid being cuckolded, and most extra-pair copulation occurs away from nest sites. Males may sometimes have multiple mates, and bigamy is mostly limited by aggression between females. Many birds do not find a nest and a mate, and instead may serve as helpers around the nest for mated pairs, a role which increases the chances of being chosen to replace a lost mate. Lost mates of both sexes can be replaced quickly during the breeding season. The formation of a pair and the bond between the two birds is tied to the holding of a nest site, though paired house sparrows can recognise each other away from the nest.

House sparrows in natural small populations, as can occur on islands, exhibit inbreeding depression. Inbreeding depression is manifested as lower survival probability and production of fewer offspring, and can occur as a result of the expression of deleterious recessive alleles. Tree hollows are more commonly used in North America than in Europe, putting the sparrows in competition with bluebirds and other North American cavity nesters, and thereby contributing to their population declines. Nests typically have external dimensions of 20 × 30 cm (8 × 12 in), but their size varies greatly. House sparrows do not hold territories, but they defend their nests aggressively against intruders of the same sex.

House sparrows' nests support a wide range of scavenging insects, including nest flies such as Neottiophilum praestum, Protocalliphora blowflies, and over 1,400 species of beetle.

Eggs and young

thumb|left|Eggs in a nest

Clutches usually comprise four or five eggs, though numbers from one to 10 have been recorded. At least two clutches are usually laid, and up to seven a year may be laid in the tropics or four a year in temperate latitudes. When fewer clutches are laid in a year, especially at higher latitudes, the number of eggs per clutch is greater. Central Asian house sparrows, which migrate and have only one clutch a year, average 6.5 eggs in a clutch. Clutch size is also affected by environmental and seasonal conditions, female age, and breeding density.

thumb|alt=Naked and blind chick|A hatchling with yellow [[Beak#Gape|gape]]

Some intraspecific brood parasitism occurs, and instances of unusually large numbers of eggs in a nest may be the result of females laying eggs in the nests of their neighbours. Such foreign eggs are sometimes recognised and ejected by females. The house sparrow is a victim of interspecific brood parasites, but only rarely, since it usually uses nests in holes too small for parasites to enter, and it feeds its young foods unsuitable for young parasites. In turn, the house sparrow has once been recorded as a brood parasite of the American cliff swallow.

thumb|left|A juvenile, showing its pink bill and obvious nestling [[gape—the soft, swollen base, which becomes harder and less swollen as the bird matures]]

The eggs are white, bluish white, or greenish white, spotted with brown or grey. Subelliptical in shape, and an average surface area of . Eggs from the tropical subspecies are distinctly smaller. Eggs begin to develop with the deposition of yolk in the ovary a few days before ovulation. In the day between ovulation and laying, egg white forms, followed by eggshell. Eggs laid later in a clutch are larger, as are those laid by larger females, and egg size is hereditary. Eggs decrease slightly in size from laying to hatching. The yolk comprises 25% of the egg, the egg white 68%, and the shell 7%. Eggs are watery, being 79% liquid, and otherwise mostly protein.

The female develops a brood patch of bare skin and plays the main part in incubating the eggs. The male helps, but can only cover the eggs rather than truly incubate them. The female spends the night incubating during this period, while the male roosts near the nest. Eggs hatch at the same time, after a short incubation period lasting 11–14 days, and exceptionally for as many as 17 or as few as 9. The length of the incubation period decreases as ambient temperature increases later in the breeding season.

Young house sparrows remain in the nest for 11 to 23 days, normally 14 to 16 days.

The chicks' eyes open after about 4 days and, at an age of about 8 days, the young birds get their first down. All the young in the nest leave it during the same period of a few hours. At this stage, they are normally able to fly. They start feeding themselves partly after 1 or 2 days, and sustain themselves completely after 7 to 10 days, 14 at the latest.

Survival

In adult house sparrows, annual survival is 45–65%. After fledging and leaving the care of their parents, young sparrows have a high mortality rate, which lessens as they grow older and more experienced. Only about 20–25% of birds hatched survive to their first breeding season. The oldest known wild house sparrow lived for nearly two decades; it was found dead 19 years and 9 months after it was ringed in Denmark. The oldest recorded captive house sparrow lived for 23 years. The typical ratio of males to females in a population is uncertain due to problems in collecting data, but a very slight preponderance of males at all ages is usual.

Predation

thumb|A male sparrow being eaten by a [[Cat|domestic cat. Cats are one of the main predators of the house sparrow.]]

The house sparrow's main predators are cats and birds of prey, but many other animals prey on them, including corvids, squirrels, and even humans—the house sparrow has been consumed in the past by people in many parts of the world, and it still is in parts of the Mediterranean. Most species of birds of prey have been recorded preying on the house sparrow in places where records are extensive. Accipiters and the merlin in particular are major predators, though cats are likely to have a greater impact on house sparrow populations. The house sparrow is also a common victim of roadkill; on European roads, it is the bird most frequently found dead.

Parasites and disease

The house sparrow is host to a huge number of parasites and diseases, and the effect of most is unknown. Ornithologist Ted R. Anderson listed thousands, noting that his list was incomplete. The commonly recorded bacterial pathogens of the house sparrow are often those common in humans, and include Salmonella and Escherichia coli. Salmonella is common in the house sparrow, and a comprehensive study of house sparrow disease found it in 13% of sparrows tested. Salmonella epidemics in the spring and winter can kill large numbers of sparrows. The house sparrow hosts avian pox and avian malaria, which it has spread to the native forest birds of Hawaii. Many of the diseases hosted by the house sparrow are also present in humans and domestic animals, for which the house sparrow acts as a reservoir host. Arboviruses such as the West Nile virus, which most commonly infect insects and mammals, survive winters in temperate areas by going dormant in birds such as the house sparrow. A few records indicate disease extirpating house sparrow populations, especially from Scottish islands, but this seems to be rare. House sparrows are also infected by haemosporidian parasites, but less so in urban than in rural areas Toxoplasma gondii has been detected in sparrows in northwestern China where they pose a risk due to their meat being consumed in the region.

The house sparrow is infested by a number of external parasites, which usually cause little harm to adult sparrows. In Europe, the most common mite found on sparrows is Proctophyllodes, the most common ticks are Argas reflexus and Ixodes arboricola, and the most common flea on the house sparrow is Ceratophyllus gallinae. Dermanyssus blood-feeding mites are also common ectoparasites of house sparrows, and these mites can enter human habitation and bite humans, causing a condition known as gamasoidosis. A number of chewing lice occupy different niches on the house sparrow's body. Menacanthus lice occur across the house sparrow's body, where they feed on blood and feathers, while Brueelia lice feed on feathers and Philopterus fringillae occurs on the head.

Physiology

House sparrows express strong circadian rhythms of activity in the laboratory. They were among the first bird species to be seriously studied in terms of their circadian activity and photoperiodism, in part because of their availability and adaptability in captivity, but also because they can "find their way" and remain rhythmic in constant darkness.

Relationships with humans

thumb|Flocking and chirping together beneath a [[fluorescent tube light in Germany]]

The house sparrow is closely associated with humans. They are believed to have become associated with humans around 10,000 years ago. The Turkestan subspecies (P. d. bactrianus) is least associated with humans and considered to be evolutionarily closer to the ancestral noncommensal populations. Usually, the house sparrow is regarded as a pest, since it consumes agricultural products and spreads disease to humans and their domestic animals. Even birdwatchers often hold it in little regard because of its molestation of other birds. However, the house sparrow can be beneficial to humans, as well, especially by eating insect pests, and attempts at the large-scale control of the house sparrow have failed. Sparrows were also trapped as food for falconers' birds and zoo animals. During the 1870s, there were debates on the damaging effects of sparrows in the House of Commons in England. In the early part of the 20th century, sparrow clubs culled many millions of birds and eggs in an attempt to control numbers of this perceived pest, but with only a localised impact on numbers. Sparrows were also persecuted in Germany from at least 1650 until 1970. House sparrows have been kept as pets at many times in history, though they have no bright plumage or attractive songs, and raising them is difficult. The house sparrow has an extremely large range and population, so it is assessed as least concern for conservation on the IUCN Red List. These declines were first noticed in North America, where they were initially attributed to the spread of the house finch, but have been most severe in Western Europe. Declines have even occurred in Australia, where the house sparrow was introduced recently. While no serious declines had been reported from Eastern Europe by 2006, as of 2023, a 50% decrease of the sparrow population has been registered in Bulgaria.

In Europe, citizen science data from a 21-year study found its numbers had dwindled in its native range in Europe by nearly 60% by 2021. In Great Britain, populations peaked in the early 1970s, but have since declined by 68% overall, and about 90% in some regions. The RSPB lists the house sparrow's UK conservation status as red. In London, the house sparrow almost disappeared from the central city. so the house sparrow is even considered an endangered species. This status came to widespread attention after a female house sparrow, referred to as the "dominomus", was killed after knocking down dominoes arranged as part of an attempt to set a world record. These declines are not unprecedented, as similar reductions in population occurred when the internal combustion engine replaced horses in the 1920s and a major source of food in the form of grain spillage was lost.

Declines have been particularly apparent even in North America, where the house sparrow is invasive in some states. Introduced to Philadelphia initially in 1852 the house sparrow rapidly spread across the nation. However, the bird has largely disappeared from the city nowadays and is estimated to have declined in North America by 84% since 1966.

In South Asia, the house sparrow has largely vanished from many major cities. In general, the house sparrow population has been on the decline in many Asian countries, particularly in India. possibly facilitated by the elimination of bushes which the sparrows use to hide, and diseases A shortage of nesting sites caused by changes in urban building design is probably a factor, and conservation organisations have encouraged the use of special nest boxes for sparrows. A primary cause of the decline seems to be an insufficient supply of insect food for nestling sparrows. Declines in insect populations result from an increase of monoculture crops, the heavy use of pesticides, the replacement of native plants in cities with introduced plants and parking areas, and possibly the introduction of unleaded petrol, which produces toxic compounds such as methyl nitrite.

Protecting insect habitats on farms and planting native plants in cities benefit the house sparrow, as does establishing urban green spaces. To raise awareness of threats to the house sparrow, World Sparrow Day has been celebrated on 20 March since 2010.

To promote conservation, in 2012, the house sparrow was declared as the state bird of Delhi.

Cultural associations

thumb|Bruno Liljefors - House sparrows among the thorns (1886)

To many people across the world, the house sparrow is the most familiar wild animal and, because of its association with humans and familiarity, it is frequently used to represent the common and vulgar, or the lewd. One of the reasons for the introduction of house sparrows throughout the world was their association with the European homeland of many immigrants. In particular, sparrows were associated by the ancient Greeks with Aphrodite, the goddess of love, due to their perceived lustfulness, an association echoed by later writers such as Chaucer and Shakespeare. Jesus's use of "sparrows" as an example of divine providence in the Gospel of Matthew also inspired later references, such as that in Shakespeare's Hamlet and the hymn His Eye Is on the Sparrow.

References

Works cited

External links

House sparrow at the Royal Society for the Protection of Birds website
Indian sparrow and house sparrow at Birds of Kazakhstan
World Sparrow Day
House sparrow Structured guide to the species in southern Africa