The rock dove or rock pigeon (/ˈpɪdʒ.ən/ also /ˈpɪdʒ.ɪn/; Columba livia) is a member of the bird family Columbidae (doves and pigeons).624 in common usages, this bird is often simply referred to as the "pigeon".
The species includes the domestic pigeon, including
the fancy pigeon. Escaped domestic pigeons have raised the populations
of feral pigeons around the world.
Wild rock doves are pale grey with two black bars on each
wing, while domestic and feral pigeons are very variable in colour
and pattern. Few differences are seen between males and females. The
species is generally monogamous, with two squabs (young) per brood.
Both parents care for the young for a time.
Habitats include various open and semiopen
environments. Cliffs and rock ledges are used for roosting and
breeding in the wild. Originally found wild in Europe, North Africa, and
western Asia, pigeons have become established in cities around the world. The
species is abundant, with an estimated population of 17 to 28 million feral and
wild birds in Europe.
Taxonomy and naming
The rock dove was first described by Gmelin in
1789. The genus name Columba is the Latin word meaning
"pigeon, dove",whose older etymology comes from the Ancient
Greek κόλυμβος (kolumbos), "a diver", from κολυμβάω (kolumbao),
"dive, plunge headlong, swim". Aristophanes (Birds, 304)
and others use the word κολυμβίς (kolumbis), "diver", for the name of
the bird, because of its swimming motion in the air. The specific epithet is
derived from the Latin livor, "bluish". Its closest
relative in the Columba genus is the hill pigeon, followed by
the other rock pigeons: the snow, speckled and white-collared
pigeons.
Subspecies
Twelve subspecies are recognized by Gibbs (2000); some of
these may be derived from feral stock.176–179
C. l. livia, the nominate subspecies, occurs in western
and southern Europe, northern Africa, and Asia to western Kazakhstan, the
northern Caucasus, Georgia, Cyprus, Turkey, Iran,
and Iraq.
C. l. atlantis (Bannerman, 1931) of Madeira,
the Azores and Cape Verde, is a very variable population with
chequered upperparts obscuring the black wing bars, and is almost certainly
derived from feral pigeons.
C. l. canariensis (Bannerman, 1914) of
the Canary Islands, is smaller and averages darker than the nominate
subspecies.
C. l. gymnocyclus (Gray, 1856)
from Senegal and Guinea to Ghana, Benin and Nigeria is
smaller and very much darker than nominate C. l. livia. It is almost
blackish on the head, rump and under parts with a white back and the
iridescence of the nape extending onto the head.
C. l. targia (Geyr von Schweppenburg, 1916) breeds
in the mountains of the Sahara east to Sudan. It is slightly
smaller than the nominate form, with similar plumage, but the back is
concolorous with the mantle instead of white.
C. l. dakhlae (Richard Meinertzhagen, 1928) is
confined to the two oases in central Egypt. It is smaller and much paler
than the nominate subspecies.
C. l. schimperi (Bonaparte, 1854) is found in
the Nile Delta south to northern Sudan. It closely resembles C.
l. targia, but has a distinctly paler mantle.
C. l. palaestinae (Zedlitz, 1912) occurs
from Syria to Sinai and Arabia. It is slightly larger
than C. l. schimperi and has darker plumage.
C. l. gaddi (Zarodney & Looudoni, 1906), breeds
from Azerbaijan and Iran east to Uzbekistan is
larger and paler than C. l. palaestinae with which it intergrades in
the west. It also intergrades with the next subspecies to the east.
C. l. neglect (Hume, 1873), is found in the
mountains of eastern Central Asia. It is similar to the nominate subspecies in
size, but is darker with a stronger and more extensive iridescent sheen on the
neck. It intergrades with the next race in the south.
C. l. intermedia (Strickland, 1844) occur
in Sri Lanka and in India south of
the Himalayan range of C. l. neglecta. It is similar to that
subspecies, but darker with a less contrasting back.
C. l. Nigerians (Buturlin, 1908)
in Mongolia and north China is variable and probably
derived from feral stock.
Bright orange eyes of a pigeon
Description
Bright orange eyes of a pigeon
A distinctive operculum is located on top of
the beak
The adult of the nominate subspecies of the rock dove is
29 to 37 cm (11 to 15 in) long with a 62 to 72 cm (24 to
28 in) wingspan. Weight for wild or feral rock doves ranges from
238–380 g (8.4–13.4 oz), though overfed domestic and semi-domestic
individuals can exceed normal weights. It has a dark bluish-grey head, neck,
and chest with glossy yellowish, greenish, and reddish-purple iridescence along
its neck and wing feathers. The iris is orange, red or golden with a paler
inner ring, and the bare skin round the eye is bluish-grey. The bill is
grey-black with a conspicuous off-white cere, and the feet are purplish-red.
Among standard measurements, the wing chord is typically around
22.3 cm (8.8 in), the tail is 9.5 to 11 cm (3.7 to
4.3 in), the bill is around 1.8 cm (0.71 in) and the tarsus is
2.6 to 3.5 cm (1.0 to 1.4 in).
The adult female is almost identical to the male, but the
iridescence on the neck is less intense and more restricted to the rear and
sides, while that on the breast is often very obscure.
The white lower back of the pure rock dove is its best
identification character; the two black bars on its pale grey wings are also
distinctive. The tail has a black band on the end and the outer web of the tail
feathers are margined with white. It is strong and quick on the wing, dashing
out from sea caves, flying low over the water, its lighter grey rump showing
well from above.
When circling overhead, the white underwing of the bird
becomes conspicuous. In its flight, behaviour, and voice, which is more of a
dovecot coo than the phrase of the wood pigeon, it is a typical
pigeon. Although it is a relatively strong flier, it also glides frequently,
holding its wings in a very pronounced V shape as it does. Though fields are
visited for grain and green food, it is often not plentiful enough as to be a
viewed as pest.Pigeons feed on the ground in flocks or individually.
They roost together in buildings or on walls or statues. When drinking, most
birds take small sips and tilt their heads backwards to swallow the water.
Pigeons are able to dip their bills into the water and drink continuously
without having to tilt their heads back. When disturbed, a pigeon in a group
will take off with a noisy clapping sound.
Pigeons,
especially homing or carrier breeds, are well known for
their ability to find their way home from long distances. Despite these
demonstrated abilities, wild rock doves are sedentary and rarely leave their
local areas.
Distribution and
habitat
The rock dove has a
restricted natural resident range in western and
southern Europe, North Africa, and into South Asia. The rock
dove is often found in pairs in the breeding season but is usually
gregarious. The species (including ferals) has a large range, with an
estimated global extent of occurrence of
10,000,000 km2 (3,900,000 sq mi). It has a large global population,
including an estimated 17–28 million individuals in
Europe. Fossil evidence suggests the rock dove originated in southern
Asia and skeletal remains unearthed in Israel confirm their existence
there for at least three hundred thousand years. However, this species has
such a long history with humans that it is impossible to tell exactly where the
species' original range was. Its habitat is natural cliffs, usually on
coasts. Its domesticated form, the feral pigeon, has been widely introduced
elsewhere, and is common, especially in cities, over much of the world. A rock
pigeon's lifespan is anywhere from 3–5 years in the wild to 15 years in
captivity, though longer-lived specimens have been reported. The main
causes of mortality in the wild are predators and persecution by
humans.[citation needed] The species was first introduced to North
America in 1606 at Port Royal, Nova Scotia.
Reproduction
The rock dove breeds at any time of the year, but peak
times are spring and summer. Nesting sites are along coastal cliff faces, as
well as the artificial cliff faces created by apartment buildings with
accessible ledges or roof spaces.
The nest is a flimsy platform of straw and
sticks, laid on a ledge, under cover, often on the window ledges of
buildings. Two white eggs are laid; incubation is shared by both parents
lasting from 17 to 19 days. The newly hatched squab (nestling)
has pale yellow down and a flesh-coloured bill with a dark band. For the first
few days, the baby squabs are tended and fed (through regurgitation)
exclusively on "crop milk" (also called "pigeon milk" or
"pigeon's milk"). The pigeon milk is produced in the crops of both
parents in all species of pigeons and doves. The fledging period is about 30
days.
Predators
With only its flying abilities protecting it from
predation, rock pigeons are a favourite almost around the world for a wide
range of raptorial birds. In fact, with feral pigeons existing in almost every
city in the world, they may form the majority of prey for several raptor
species that live in urban areas. Peregrine falcons and Eurasian
sparrow hawks are natural predators of pigeons that are quite adept at
catching and feeding upon this species. Up to 80% of the diet of peregrine
falcons in several cities that have breeding falcons is composed of feral
pigeons. Some common predators of feral pigeons in North America
are opossums, raccoons, red-tailed hawks, great horned
owls, eastern screech owls, and Accipiter’s. The birds that prey on
pigeons in North America can range in size from American
kestrels to golden eagles and can even
include gulls, crows, and ravens. On the ground, the
adults, their young, and their eggs are at risk from feral and
domestic cats. Doves and pigeons are considered to be game
birds, as many species have been hunted and used for food in many of the
countries in which they are native.
The body feathers have dense, fluffy bases and
are loosely attached to the skin, hence they drop out easily. When a predator
catches it, large numbers of feathers come out in the attacker's mouth and the
temporary distraction is used by the pigeon to make an escape.] They also
tend to drop the tail feathers when preyed upon or under traumatic conditions,
probably as a distraction mechanism.
Preening
Pigeons primarily use
powder down feathers for preening which gives them a soft and silky feel to
their plumage which is unmatched by other birds. Pigeons have no preen gland or
at times have very rudimentary preen glands, so that oil is not used for
preening. Powder down feathers are spread across the body which have a tendency
to disintegrate and the powder, akin to talcum powder, is used all over the
feathers for plumage maintenance. Some subspecies of domestic pigeons have
modified feathers called "fat quills". These feathers contain yellow
oil-like fat that derives from the same cells as powder down. This is used
while preening and helps in plumage maintenance by reducing bacterial
degradation of feathers by feather bacili.
Parasites
Pigeons may harbor a
diverse parasite fauna. They often host the intestinal helminthes Capillaries
columbine and Acaridae columbine. Their ectoparasites include
the ischnoceran lice Columbicola columbae, Campanologers
bidentatus compare, the amblyceran lice binomially columbine, Hohorstiella
late, Colpocephalum turbinate, the mites Tinaminyssus mellow, Dermanyssus
gallinae, Dermoglyphus columbae, Falculifer prostrates,
and Diplaegidia columbae. The hippoboscidfly Pseudolynchia
canariensis is a typical blood-sucking ectoparasite of pigeons, found only
in tropical and subtropical regions.
Human health
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