Eurasian tree sparrow
From Wikipedia, the free encyclopedia
The Eurasian
tree sparrow (Passer montanus) is a passerine bird
in the sparrow family with a
rich chestnut crown and nape,
and a black patch on each pure white cheek. The sexes are similarly plumaged,
and young birds are a duller version of the adult. This sparrow breeds over
most of temperate Eurasia and Southeast
Asia, where it is known as the tree sparrow,
and it has been introduced elsewhere including the United States, where it is
known as the Eurasian tree sparrow or German sparrow to
differentiate it from the native unrelated American tree sparrow.
Although several subspecies are recognised, the appearance of this bird varies
little across its extensive range.
The Eurasian tree
sparrow's untidy nest is built in a natural cavity, a hole in a building or the
large nest of a European
magpie or white
stork. The typical clutch is
five or six eggs which hatch in under two weeks. This sparrow feeds mainly on
seeds, but invertebrates are also consumed, particularly during the breeding
season. As with other small birds, infection by parasites and diseases, and
predation by birds of prey take
their toll, and the typical life span is about two years.
The Eurasian tree
sparrow is widespread in the towns and cities of eastern Asia, but in Europe it
is a bird of lightly wooded open countryside, with the house
sparrow breeding in the more urban areas. The Eurasian
tree sparrow's extensive range and large population ensure that it is not
endangered globally, but there have been large declines in western European
populations, in part due to changes in farming practices involving increased
use of herbicides and loss of winter stubble fields. In eastern Asia and western
Australia, this species is sometimes viewed as a pest, although it is also
widely celebrated in oriental art.
Description
The
Eurasian tree sparrow is 12.5–14 cm (5–5½ in) long, with a wingspan of
about 21 cm (8.25 in) and a weight of 24 g
(0.86 oz), making it roughly 10% smaller than the house
sparrow. The adult's crown and nape are rich chestnut,
and there is a kidney-shaped black ear patch on each pure white cheek; the
chin, throat, and the area between the bill and throat are black. The
upperparts are light brown, streaked with black, and the brown wings have two
distinct narrow white bars. The legs are pale brown, and the bill is lead-blue
in summer, becoming almost black in winter.
This sparrow is
distinctive even within its genus in that it has no plumage differences between
the sexes; the juvenile also resembles the adult, although the colours tend to
be duller. Its contrasting face pattern makes this species easily
identifiable in all plumages; the smaller size and brown, not grey, crown
are additional differences from the male house sparrow. Adult and juvenile
Eurasian tree sparrows undergo a slow complete moult in
the autumn, and show an increase in body mass despite a reduction in stored
fat. The change in mass is due to an increase in blood volume to support active
feather growth, and a generally higher water content in the body.
The Eurasian tree
sparrow has no true song, but its vocalisations include an excited series
of tschip calls given by unpaired or courting males. Other
monosyllabic chirps are used in social contacts, and the flight call is a harshteck.[4] A
study comparing the vocalisations of the introduced Missouri population with
those of birds from Germany showed that the US birds had fewer shared syllable
types (memes)
and more structure within the population than the European sparrows. This may
have resulted from the small size of the founding North American population and
a consequent loss of genetic
diversity.[8]
Taxonom
Description
of the house and Eurasian tree sparrows from theSystema naturae
The Old World sparrow genus Passer is
a group of small passerine birds that is
believed to have originated in Africa, and which contains 15–25 species
depending on the authority. Its members are typically found in open,
lightly wooded, habitats, although several species, notably the house
sparrow (P. domesticus) have adapted to human
habitations. Most species in the genus are typically 10–20 cm
(4–8 in) long, predominantly brown or greyish birds with short square
tails and stubby conical beaks. They are primarily ground-feeding seed-eaters,
although they also consume invertebrates, especially when breeding.] Genetic
studies show that the Eurasian tree sparrow diverged from the other Eurasian
members of its genus relatively early, before the speciation of
the house, plain-backed and Spanish
sparrows. The Eurasian species is not closely related to
the American tree sparrow (Spizelloides
arborea), which is an American
sparrow.
The Eurasian tree
sparrow's binomial name is derived from two Latin words: passer,
"sparrow", and montanus, "of the mountains"
(from mons "mountain"). The Eurasian tree
sparrow was first described by Carl
Linnaeus in his 1758 Systema Naturae as Fringilla
montana,] but,
along with the house sparrow, it was soon moved from the finches (family
Fringillidae) into the new genus Passer created by French
zoologistMathurin Jacques
Brisson in 1760. The Eurasian tree sparrow's common
name is given because of its preference of tree holes for nesting. This name,
and the scientific name montanus, do not appropriately describe
this species's habitat preferences: the German name Feldsperling ("field
sparrow") comes closer to doing so.[17]
Subspecies
This species varies
little in appearance across its large range, and the differences between the
seven extant subspecies recognised by
Clement are slight. At least 15 other subspecies have been proposed, but are
considered to be intermediates of the listed races
P. m. montanus,
the nominate subspecies,
ranges across Europe except southwestern Iberia,
southern Greece, and the
former Yugoslavia. It also breeds in
Asia east to the Lena River and south to
the northern regions ofTurkey, the Caucasus, Kazakhstan, Mongolia and Korea.
·
P. m.
transcaucasicus, described by Sergei
Aleksandrovich Buturlin in 1906,
breeds from the southern Caucasus east to northern Iran.
It is duller and greyer than the nominate race.
·
P. m. dilutus,
described by Charles Wallace
Richmond in 1856, is resident in the extreme northeast of
Iran, northern Pakistan and
northwest India. It also occurs
further north, from Uzbekistan and Tajikistan east
to China.
Compared to P. m. montanus, it is paler, with sandy-brown
upperparts.
·
P. m. tibetanus,
the largest race by size, was described by Stuart Baker in
1925. It is found in the northern Himalayas,
from Nepal east
through Tibet to
northwest China. It resembles P. m. dilutus, but is darker.
·
P. m. saturatus,
described by Leonhard Hess
Stejneger in 1885, breeds in Sakhalin,
the Kuril Islands, Japan, Taiwan and South
Korea. It is deeper brown than the nominate subspecies and
has a larger bill. P. m. malaccensis, described by Alphonse Dubois in
1885, is found from the southern Himalayas east to Hainan and Indonesia.
It is a dark race, like P. m. saturatus, but is smaller and more
heavily streaked on its upperparts.
·
P. m. hepaticus,
described by Sidney Dillon Ripley in
1948, breeds from northeast Assam to
northwest Burma. It is similar
to P. m. saturatus, but redder on its head and upperparts.
Distribution and habitat
The Eurasian tree
sparrow's natural breeding range comprises most of temperate Europe
and Asia south of about latitude 68°N (north
of this the summers are too cold, with July average temperatures below
12 °C) and through Southeast Asia to Java and Bali.
It formerly bred in the Faroes, Malta and Gozo. In
South Asia it is found mainly in the temperate zone. It is sedentary over
most of its extensive range, but northernmost breeding populations migrate south
for the winter,] and
small numbers leave southern Europe for North Africa and the Middle East.] The
eastern subspecies P. m. dilutus reaches coastal Pakistan in
winter and thousands of birds of this race move through eastern China in
autumn.
The Eurasian tree
sparrow has been introduced outside
its native range, but has not always become established, possibly due to
competition with the house sparrow. It was introduced successfully to Sardinia,
eastern Indonesia, the Philippines and Micronesia,
but introductions to New
Zealand and Bermuda did
not take root. Ship-carried birds colonised Borneo.
This sparrow has occurred as a natural vagrant to Gibraltar, Tunisia, Algeria,Egypt, Israel,
and Dubai.
In North America, a
population of about 15,000 birds has become established around St. Louis and
neighbouring parts of Illinois and southeastern Iowa.] These
sparrows are descended from 12 birds imported from Germany and released in late
April 1870 as part of a project to enhance the native North American avifauna.
Within its limited US range, the Eurasian tree sparrow has to compete with the
house sparrow in urban centres, and is therefore mainly found in parks, farms
and rural woods. The American population is sometimes referred to as the "German
sparrow", to distinguish it from both the native American tree sparrow
species and the much more widespread "English" house sparrow.
In Australia, the
Eurasian tree sparrow is present in Melbourne,
towns in central and northern Victoria and
some centres in the Riverina region
of New South Wales.
It is a prohibited species in Western
Australia, where it often arrives on ships from Southeast Asia.
Despite its
scientific name, Passer montanus, this is not typically a mountain
species, and reaches only 700 m (2,300 ft) in Switzerland,
although it has bred at 1,700 m (5,600 ft) in the northern Caucasus
and as high as 4,270 m (14,000 ft) in Nepal. In Europe, it is
frequently found on coasts with cliffs, in empty buildings, in pollarded willows
along slow water courses, or in open countryside with small isolated patches of
woodland. The Eurasian tree sparrow shows a strong preference for
nest-sites near wetland habitats, and
avoids breeding on intensively managed mixed farmland.
When the Eurasian
tree sparrow and the larger house sparrow occur in the same area, the house
sparrow generally breeds in urban areas while the smaller Eurasian tree sparrow
nests in the countryside. Where trees are in short supply, as in Mongolia,
both species may utilise man-made structures as nest sites.] The
Eurasian tree sparrow is rural in Europe, but is an urban bird in eastern Asia;
in southern and central Asia, both Passer species may be found
around towns and villages. In parts of the Mediterranean, such as Italy, both
the Tree and the Italian or Spanish sparrows may be found in
settlements. In Australia, the Eurasian tree sparrow is largely an urban
bird, and it is the house sparrow which utilises more natural habitats.
Behaviour and ecology
The Eurasian tree
sparrow reaches breeding maturity within a year from hatching, and
typically builds its nest in a cavity in an old tree or rock face. Some nests
are not in holes as such, but are built among roots of overhanging gorse or
similar bush. Roof cavities in houses may be used, and in the tropics, the
crown of a palm tree or the ceiling of a verandah can serve as a nest site.
This species will breed in the disused domed nest of a European
magpie, or an active or unused stick nest of a large
bird such as the white stork,] white-tailed eagle, osprey, black
kite or grey
heron. It will sometimes attempt to take over the nest of
other birds that breed in holes or enclosed spaces, such as the barn
swallow, house
martin, sand
martin or European bee-eater.
Pairs may breed in
isolation or in loose colonies,] and
will readily use nest boxes. In a Spanish
study, boxes made from a mixture of wood and concrete (woodcrete) had a much
higher occupancy rate than wooden boxes (76.5% versus 33.5%), and birds nesting
in woodcrete sites had earlier clutches, a shorter incubation period and more
breeding attempts per season. Clutch size and chick condition did not differ
between nest box types, but reproductive success was higher in woodcrete,
perhaps because the synthetic nests were 1.5 °C warmer than their wooden
counterparts.
The male calls from
near the nest site in spring to proclaim ownership and attract a mate. He may
also carry nest material into the nest hole. The display and nest building is
repeated in autumn. The preferred locations for the autumn display are old
Eurasian tree sparrow nests, particularly those where nestlings had hatched.
Empty nest boxes, and sites used by house sparrows or other hole nesting birds,
such as tits, pied flycatchers orcommon
redstarts, are rarely used for the autumn display.
The untidy nest is
composed of hay, grass, wool or other
material and lined with feathers, which
improve the thermal insulation.] A
complete nest consists of three layers; base, lining and dome.] The
typical clutch is five or six eggs (rarely
more than four in Malaysia), white to pale grey and heavily marked with spots,
small blotches, or speckling; they are 20 x 14 mm
(0.8 x 0.6 in) in size and weigh 2.1 g (0.08 oz), of
which 7% is shell. The eggs are incubated by both parents for 12–13 days
before the altricial, naked chicks
hatch, and a further 15–18 days elapse before they fledge.
Two or three broods may be raised each year; birds breeding in colonies
produce more eggs and fledglings from their first broods than solitary pairs,
but the reverse is true for second and third clutches. Females which
copulate frequently tend to lay more eggs and have a shorter incubation time,
so within-pair mating may be an indicator of the pairs' reproductive
ability. There is a significant level of promiscuity; in a Hungarian
study, more than 9% of chicks were sired by extra-pair males, and 20% of the broods
contained at least one extra-pair young.
Hybridisation between
the Eurasian tree sparrow and the house sparrow has been recorded in many parts
of the world with male hybrids tending to resemble the Eurasian tree sparrow
while females have more similarities with the house sparrow. A breeding
population in the Eastern
Ghats of India, said to be introduced, may
also hybridise with house sparrows. On at least one occasion a mixed pair
has resulted in fertile young. A wild hybridisation with the resident
sparrows of Malta, which are intermediate between theSpanish
sparrow (P. hispaniolensis) and Italian
sparrows (P. italiae), was recorded in Malta in
1975.
The tree sparrow is
a predominantly seed and grain eating bird which feeds on the ground in flocks,
often with house sparrows, finches, or buntings. It eats weed seeds, such
as chickweeds and goosefoot,
spilled grain, and it may also visit feeding
stations, especially for peanuts.
It will also feed on invertebrates,
especially during the breeding season when the young are fed mainly on animal
food; it takes insects, woodlice, millipedes, centipedes,spiders and harvestmen.
Adults use a
variety of wetlands when foraging for invertebrate prey to feed nestlings, and
aquatic sites play a key role in providing adequate diversity and availability
of suitable invertebrate prey to allow successful chick rearing throughout the
long breeding season of this multi-brooded species. Large areas of formerly
occupied farmland no longer provide these invertebrate resources due to the
effects of intensive farming,
and the availability of supplementary seed food within 1 kilometre
(0.62 mi) of the nest-site does not influence nest-site choice, or affect
the number of young raised.
In winter, seed
resources are most likely to be a key limiting factor. At this time of
year, individuals in a flock form linear dominance hierarchies,
but there is no strong relation between the size of the throat patch and
position in that hierarchy. This is in contrast to the house sparrow; in that
species, fights to establish dominance are reduced by the display of the throat
patch, the size of which acts as a signalling "badge"
of fitness.
The risk of
predation affects feeding strategies. A study showed increased distance between
shelter and a food supply meant that birds visited a feeder in smaller flocks,
spent less time on it and were more vigilant when far from shelter. Sparrows
can feed as "producers", searching for food directly, or
"scroungers", just joining other flock members who have already
discovered food. Scrounging was 30% more likely at exposed feeding sites,
although this is not due to increased anti-predator vigilance. A possible
explanation is that riskier places are used by individuals with lower fat
reserves. Predators of the tree sparrow include a variety of accipiters, falcons and owls,
such as the Eurasian sparrowhawk, common kestrel, little
owl, and sometimes long-eared
owl and white stork. It does not appear to be
at an increased risk of predation during its autumn moult, despite having fewer
flight feathers at that time. Nests may be raided by Eurasian magpies, jays, least
weasels, rats, cats and constricting snakes such as thehorseshoe whip snake.
Many species
of birdlice are present on the birds and in
their nests, and mites of the genus Knemidocoptes have
been known to infest populations, resulting in lesions on the legs and
toes. Parasitisation of nestlings byProtocalliphora blow-fly larvae
is a significant factor in nestling mortality. Egg size does not influence
nestling mortality, but chicks from large eggs grow faster.
Tree sparrows are also
subject to bacterial and viral infections. Bacteria have been shown to be an
important factor in the failure of eggs to hatch and in nestling
mortality, and mass deaths due to Salmonella infection
have been noted in Japan. Avian
malaria parasites have been found in the blood of many
populations, and birds in China were found to harbour a strain of H5N1 that
was highly virulent to chickens.
The immune response
of tree sparrows is less robust than that of the house sparrow and has been
proposed as a factor in the greater invasive potential of the latter. The
house sparrow and tree sparrow are the most frequent victims of roadkill on
the roads of Central, Eastern and Southern Europe The maximum recorded age
is 13.1 years, but three years is a typical lifespan.
The tree sparrow
has a large, currently unquantified range; its world population is also
unknown, but includes an estimated 52–96 million individuals in Europe.
Although population trends have not been evaluated, the species is not believed
to approach the thresholds for the population decline criterion of the IUCN
Red List (that is, declining more than 30% in ten years
or three generations). For these reasons, the species' conservation status is
evaluated at the global level as "Least
Concern".
Although the tree
sparrow has been expanding its range in Fennoscandia and
eastern Europe, populations have been declining in much of western
Europe, a trend reflected in other farmland birds such as the skylark,corn
bunting and northern
lapwing. From 1980 to 2003, common farmland bird numbers fell
by 28%. The collapse in populations seems to have been particularly severe
in Great Britain, where there was a 95% decline between 1970 and 1998, and
Ireland, which had only 1,000–1,500 pairs in the late 1990s. In the
British Isles, such declines may be due to natural fluctuations, to which tree
sparrows are known to be prone. Breeding performance has improved substantially
as population sizes have decreased, suggesting that decreases in productivity
were not responsible for the decline and that survival was the critical
factor. The large decline in tree sparrow numbers is probably the result
of agricultural intensification and specialisation, particularly the increased
use of herbicides and a trend towards autumn-sown crops (at the expense of
spring-sown crops that produce stubble fields in winter). The change from mixed
to specialised farming and the increased use of insecticides has reduced the
amount of insect food available for nestlings.
Relationships with humans
The tree sparrow is
seen as a pest in some areas. In Australia, it damages many cereal and fruit
crops and spoils cereal crops, animal feed and stored grain with its
droppings. Quarantine rules
prohibit the transport of this species into Western Australia.
Chairman Mao
Zedong of China attempted in April 1958 to reduce crop
damage by tree sparrows, estimated at 4.5 kg (9.9 lb) of grain per
bird each year, by mobilising three million people and many scarecrows to drive
the birds to death by exhaustion. Although initially successful, the "great sparrow
campaign" had overlooked the numbers of locusts and other
insect pests consumed by the birds, and crop yields fell, exacerbating a famine
which led to the deaths of 30 million people between 1959 and
1961. The tree sparrow's consumption of insects has led to its use in
agriculture to control fruit tree pests and the common asparagus
beetle, Crioceris aspergi.
The tree sparrow
has long been depicted in Chinese and Japanese art, often on a plant spray or
in a flying flock, and representations by oriental artists including Hiroshige have
featured on the postage stamps of Antigua and Barbuda, Central African
Republic, China and the
Gambia. More straightforward illustrations were used on the
stamps of Belarus,Belgium, Cambodia, Estonia and Taiwan.
The fluttering of the bird gave rise to a traditional Japanese dance, the Suzume
Odori, which was depicted by artists such as Hokusai.
In the Philippines,
where it is one of several species referred to as maya, and is sometimes specifically
referred to as the "mayang simbahan" ("church maya" or
"church sparrow"), the tree sparrow is the most common bird in the
cities. Many urban Filipinos confuse it with the former national bird of the
Philippines, the black-headed munia -
also called a maya, but specifically differentiated in folk
taxa as the "mayang pula" ("red
maya").
Passer montanus
Huevos de Passer
montanus
El gorrión molinero (Passer
montanus) es una especie de ave paseriforme de la familia Passeridae. Se distribuye por la mayor parte
de la Eurasia templada y también en el norte de África. No está amenazada y
cuanto con grandes poblaciones, por ejemplo la europea se estima entre 52 y 96
millones de ejemplares. Habita en zonas forestales abiertas, habitualmente
en las proximidades de zonas humanizadas como casas o campos de cultivo.
Descripción
En el bebedero
Es un pájaro pequeño, mide entre 12,5 y 14 cm. Se
diferencia de otras especies del género Passer en su píleo pardorrojizo, sus carrillos blancos con una mancha negra en la
mejilla y su babero negro y pequeño. Su vientre y pecho son de color gris
pardusco; y su dorso es marrón con listas pequeñas negras. Presenta una banda
alar blanca bastante notable. Esta especie no presenta dimorfismo sexual acentuado. Los
jóvenes son similares, aunque con el plumaje más apagado.
Comportamiento
Es un ave gregaria, forman grandes bandos (a veces interespecíficos,
con otros gorriones y fringílidos) fuera de la época de
cría. Es una especie eminentemente sedentaria. Es una especie
principalmente granívora, aunque en la época
de cría también se alimenta de invertebrados.4
Anida en huecos de árboles y construcciones
·
P. m. iubilaeus - Este de China.
·
P. m. malaccensis - Sudeste asiático: zona central
de Myanmar, península de Malaca, Hainan, Vietnam y oeste de Indonesia.
