Bolle's Pigeon
Encyclopedia
The Bolle's Pigeon is a species of Columba
genus of the family Columbidae, of dove
s and pigeons, which is endemic
to the Canary Islands
, Spain
. This bird is named after the German naturalist Carl Bolle
, who was the first to distinguish it from the Laurel Pigeon. This Wood Pigeon is endemic
to the Laurel forest
habitat.
. Its dark grey, rather than brown plumage, and the dark bands on the grey tail distinguish it from the other pigeon endemic to the Canary Islands, the Laurel Pigeon
. It is a basically dark grey bird, with a pinkish breast. It lacks any white markings, which together with its darker plumage
distinguishes it from the other species.
With red peak, most intense at the tip. Head relatively large, slate gray, in males, with bluish or greenish metallic side of the neck and back of neck. Eyes rounded, yellow to orange with black pupil and lightly framed by a thin, flesh-colored eye ring. Back, rump and wings brownish gray, which in adult males with metallic blue shoulders. The primary and secondary remiges are blackish brown. The chest, blue-dark gray, stained purple in males. Belly is pale gray pastel. Females, less conspicuous, do not hold the highlights, reflections and metallic hues, and even the colors are more 'gray' and off.
Mainly dark grey with blacker flight feathers and paler grey tail with dark terminal band, hindneck with green and pink gloss and reddish tinge to breast. Similar: Only likely to be confused with White-tailed Laurel Pigeon Columba junoniae or dark Feral Pigeon. The voice is a guttural mournful cooing. Hints: Look for birds flying low and fast over laurel forest.
Its flight is quick, performed by regular beats, with an occasional sharp flick of the wings, characteristic of pigeons in general. It takes off with a loud clattering.
The call is a hoarse cooing.
sticks and twigs, forming the classic platform, which is usually lined with mosses and lichens briefly. It clutch one or two eggs. The egg hatch after a shared incubation of eighteen days.
Frugivore which eat drupas or fruits of canary bay (Laurus azorica), Madeira mahogany (Persea indica), (Ocotea foetens) and fayanuts of Myrica faya but can consume alternately diverse continental cultives, sweet acorns, hazelnuts, other nuts, berries...
forest zone. Bolle's Pigeon builds a stick nest in a tree, laying one white egg
. Columba bollii occurs on Tenerife particularly at Anaga and Teno, La Palma in a restricted area of the north-east), La Gomera in Garajonay National Park with some birds outside the park, and El Hierro where it occurs in Golfo and Sabinosa in the Canary Islands, Spain. It may formerly have occurred on Gran Canaria, as bones similar to those of a laurel pigeon have been found and there is a possible sight record from the late 19th century. It was common in the past, but disappeared from many areas owing to clearance of laurel forest in the islands.
More recently the rate of laurel forest clearance has been slowed or stopped. Population estimates for the species are 1,160-1,315 birds in 1980, 6,000 individuals in 2001, and 5,000-20,000 most recently. Whether these figures reveal genuine population increases is unclear, but the area of occupied territory appears to be expanding and despite several potential threats the population is at least stable, probably increasing.
In 2007, the species was estimated by SEO Sociedad Española de Ornitología, BirdLife in Spain to number 5,000-20,000 individuals.
It occurs in dense laurel forest
in mountainous areas, especially in ravines; also in heath of Myrica faya and Erica arborea, and sometimes in rather open areas, e.g. cultivation. It spends the hottest part of the day in deep shade. It feeds mainly on fruit but also takes grain and occasionally buds, leaves and shoots. It will gather in large concentrations on fruiting trees, plucking berries from the tree but also feeding on the ground. It makes some altitudinal movements to take advantage of ripe cereals and fruit at lower elevations in late summer.
Threats Historical declines resulted from intensive exploitation of laurel forests. The extent of forest loss has slowed, although fragmentation has continued in some areas as forests are exploited for poles and tool handles. A small amount of illegal hunting occurs at drinking sites. As it is a tree-nesting species, predation by introduced mammals including rats is of less significance than for C. junoniae but it remains a potential threat, the impact of which has not been fully assessed1. Grazing pressure from sheep is leading to habitat degradation on La Gomera and at El Hierro. Forest fires also pose a moderate threat to its habitat. Recreational activities cause some disturbance in the breeding season. The species is potentially threatened by outbreaks of Newcastle Disease and Tuberculosis.
The natural habitat is tall laurisilva
forest or dense tree heaths which are cloud-covered for much of the year. The forests consist mainly of Azores Laurel
, Oreodaphne foetens, Til
, Madeira Mahogany
, Canary Laurel
, Faya
, Lily of the Valley Tree
and the Picconia
. The Trocaz Pigeon prefers primary forests, but secondary growth
is used for feeding, and agricultural land is also visited, especially at times of fruit shortage. Most of the pigeons are found below 1000 m (3300 ft), and their prime environment appears to be steep ravine-indented slopes along artificial watercourses, with the occasional large dead laurel tree and much tree heath. This species is highly mobile between different areas at different times of year.
It was very abundant when the islands were first colonised by humans, but was extirpated. The losses on the islands were largely due to deforestation for wood and to create agricultural and grazing land.
The exclusion of livestock from the native forest allows it to regenerate and create more suitable habitat. Some illegal hunting and poisoning continues because of the damage this pigeon can do to crops. Perhaps the main limiting factor on the rate at which the pigeon increases its numbers is eggs and young being taken by introduced Black Rats
. It is now classed as Near Threatened
on the IUCN Red List
, an improvement on its Threatened
status in 1988. This species is protected under the European Union
Birds Directive
, and the laurel forests under the Habitats Directive.
is the largest within the pigeon family, and has the widest distribution. Its members are typically pale grey or brown, often with white head or neck markings or iridescent green or purple patches on the neck and breast. The neck feathers may be stiffened and aligned to form grooves. One of several subgroups within Columba consists of the widespread Eurasian Common Wood Pigeon, Bolle's Pigeon, the Trocaz Pigeon, and the African Afep Pigeon
. The two Macaronesia
n endemic pigeons, Bolle's and Trocaz, are thought to be derived from isolated island populations of C. palumbus.
The Atlantic archipelagos of the Canaries
, Azores
, and Madeira
have a volcanic origin and they have never been part of a continent. The formation of Madeira started in the Miocene
and the island was substantially complete by 700,000 years ago. At various times in the past, the major islands of these archipelagos were all colonised by ancestral wood pigeons, which evolved on their respective islands in isolation from the mainland populations. Mitochondrial
and nuclear
DNA
sequences suggest that the ancestor of Bolle's Pigeon may have arrived in the Canaries about 5 mya, but an older lineage that gave rise to another Canarian endemic, the Laurel Pigeon
, C. junoniae, may date from 20 mya. The most recent wood pigeon arrival on Macaronesia was that which gave rise to the subspecies C. palumbus maderensis.
The Trocaz Pigeon
was formally described in 1829 by Karl Heineken
. He recognised it as different from the now-extinct local form of the Madeiran Wood Pigeon
a sub-species of the Common Wood Pigeon. This is a monotypic species, although in the past the canarian Bolle's Pigeon was sometimes regarded as a subspecies
of the Trocaz Pigeon.
Columba
Saint Columba —also known as Colum Cille , Colm Cille , Calum Cille and Kolban or Kolbjørn —was a Gaelic Irish missionary monk who propagated Christianity among the Picts during the Early Medieval Period...
genus of the family Columbidae, of dove
Dove
Pigeons and doves constitute the bird family Columbidae within the order Columbiformes, which include some 300 species of near passerines. In general terms "dove" and "pigeon" are used somewhat interchangeably...
s and pigeons, which is endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
. This bird is named after the German naturalist Carl Bolle
Carl Bolle
Carl August Bolle was a German naturalist and collector.Bolle was born at Berlin into a wealthy brewing family. He studied medicine and natural science at Berlin and Bonn...
, who was the first to distinguish it from the Laurel Pigeon. This Wood Pigeon is endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to the Laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
habitat.
Description
Larger than the common pigeon, a length of 36 cm to 38 cm. It is a large dark grey pigeon. At 37–40 cm, it looks like a very dark Wood PigeonWood Pigeon
The Wood Pigeon is a species of bird in the Columba genus in the Columbidae family. It is a member of the dove and pigeon family Columbidae.- Distribution :...
. Its dark grey, rather than brown plumage, and the dark bands on the grey tail distinguish it from the other pigeon endemic to the Canary Islands, the Laurel Pigeon
Laurel Pigeon
The Laurel Pigeon, White-tailed Laurel Pigeon, Paloma rabiche, is a species of bird in the Columba genus in the Columbidae family. It is a member of the family Columbidae of doves and pigeons, which is endemic to the Canary Islands, Spain...
. It is a basically dark grey bird, with a pinkish breast. It lacks any white markings, which together with its darker plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
distinguishes it from the other species.
With red peak, most intense at the tip. Head relatively large, slate gray, in males, with bluish or greenish metallic side of the neck and back of neck. Eyes rounded, yellow to orange with black pupil and lightly framed by a thin, flesh-colored eye ring. Back, rump and wings brownish gray, which in adult males with metallic blue shoulders. The primary and secondary remiges are blackish brown. The chest, blue-dark gray, stained purple in males. Belly is pale gray pastel. Females, less conspicuous, do not hold the highlights, reflections and metallic hues, and even the colors are more 'gray' and off.
Mainly dark grey with blacker flight feathers and paler grey tail with dark terminal band, hindneck with green and pink gloss and reddish tinge to breast. Similar: Only likely to be confused with White-tailed Laurel Pigeon Columba junoniae or dark Feral Pigeon. The voice is a guttural mournful cooing. Hints: Look for birds flying low and fast over laurel forest.
Its flight is quick, performed by regular beats, with an occasional sharp flick of the wings, characteristic of pigeons in general. It takes off with a loud clattering.
The call is a hoarse cooing.
Ecollogy
Breeding occurs in in trees especially in February-June. The nest, something more elaborate than those of other pigeons, is built on the upper branches of a tree, with pieces ofsticks and twigs, forming the classic platform, which is usually lined with mosses and lichens briefly. It clutch one or two eggs. The egg hatch after a shared incubation of eighteen days.
Frugivore which eat drupas or fruits of canary bay (Laurus azorica), Madeira mahogany (Persea indica), (Ocotea foetens) and fayanuts of Myrica faya but can consume alternately diverse continental cultives, sweet acorns, hazelnuts, other nuts, berries...
Distribution and population
It is a resident breeder in the mountain laurisilvaLaurisilva
Laurisilva or laurissilva is a subtropical forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterised by evergreen, glossy-leaved tree species that look alike with leaves of lauroide type...
forest zone. Bolle's Pigeon builds a stick nest in a tree, laying one white egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
. Columba bollii occurs on Tenerife particularly at Anaga and Teno, La Palma in a restricted area of the north-east), La Gomera in Garajonay National Park with some birds outside the park, and El Hierro where it occurs in Golfo and Sabinosa in the Canary Islands, Spain. It may formerly have occurred on Gran Canaria, as bones similar to those of a laurel pigeon have been found and there is a possible sight record from the late 19th century. It was common in the past, but disappeared from many areas owing to clearance of laurel forest in the islands.
More recently the rate of laurel forest clearance has been slowed or stopped. Population estimates for the species are 1,160-1,315 birds in 1980, 6,000 individuals in 2001, and 5,000-20,000 most recently. Whether these figures reveal genuine population increases is unclear, but the area of occupied territory appears to be expanding and despite several potential threats the population is at least stable, probably increasing.
In 2007, the species was estimated by SEO Sociedad Española de Ornitología, BirdLife in Spain to number 5,000-20,000 individuals.
It occurs in dense laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...
in mountainous areas, especially in ravines; also in heath of Myrica faya and Erica arborea, and sometimes in rather open areas, e.g. cultivation. It spends the hottest part of the day in deep shade. It feeds mainly on fruit but also takes grain and occasionally buds, leaves and shoots. It will gather in large concentrations on fruiting trees, plucking berries from the tree but also feeding on the ground. It makes some altitudinal movements to take advantage of ripe cereals and fruit at lower elevations in late summer.
Threats Historical declines resulted from intensive exploitation of laurel forests. The extent of forest loss has slowed, although fragmentation has continued in some areas as forests are exploited for poles and tool handles. A small amount of illegal hunting occurs at drinking sites. As it is a tree-nesting species, predation by introduced mammals including rats is of less significance than for C. junoniae but it remains a potential threat, the impact of which has not been fully assessed1. Grazing pressure from sheep is leading to habitat degradation on La Gomera and at El Hierro. Forest fires also pose a moderate threat to its habitat. Recreational activities cause some disturbance in the breeding season. The species is potentially threatened by outbreaks of Newcastle Disease and Tuberculosis.
The natural habitat is tall laurisilva
Laurisilva
Laurisilva or laurissilva is a subtropical forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterised by evergreen, glossy-leaved tree species that look alike with leaves of lauroide type...
forest or dense tree heaths which are cloud-covered for much of the year. The forests consist mainly of Azores Laurel
Laurus azorica
Laurus azorica is a species of plant in the Lauraceae family, related to laurus nobilis. It is a member of the genus Laurus and is commonly known as Azores Laurel. Laurus is a genus of evergreen trees belonging to the Laurel family, Lauraceae...
, Oreodaphne foetens, Til
Ocotea foetens
Ocotea foetens is a species of tree up to 40 m tall in the Lauraceae family. It is a common constituent in the laurisilva forests of the archipelagoes of Macaronesia: Madeira and Azores , and Canaries . It is commonly called "Til", "Tilo", "Stinkwood", Garoé, Oreodaphne foetens or Rain tree of...
, Madeira Mahogany
Persea indica
Persea indica is a species of plant in the Lauraceae family.It is found in the Azores, Madeira, and Canary Islands in Macaronesia. It is threatened by habitat loss.-Overview:...
, Canary Laurel
Appolonias barbujana
Apollonias barbujana , the Canary Laurel or Barbusano, is perhaps the only species of flowering plants belonging to Apollonias genus, in the laurel family, Lauraceae....
, Faya
Myrica faya
Myrica faya is a species of Myrica, native to Macaronesia , and possibly also southern Portugal....
, Lily of the Valley Tree
Clethra arborea
Clethra arborea, commonly known as the Lily of the Valley Tree, is a flowering plant in the genus Clethra. It is found in Macaronesia where it is native to Madeira, extinct in the Canary Islands, and considered an introduced species in the Azores...
and the Picconia
Picconia excelsa
Picconia excelsa is a species of Picconia, endemic to Macaronesia, occurring on the Canary Islands and Madeira .-Description:...
. The Trocaz Pigeon prefers primary forests, but secondary growth
Secondary growth
In many vascular plants, secondary growth is the result of the activity of the two lateral meristems, the cork cambium and vascular cambium. Arising from lateral meristems, secondary growth increases the girth of the plant root or stem, rather than its length. As long as the lateral meristems...
is used for feeding, and agricultural land is also visited, especially at times of fruit shortage. Most of the pigeons are found below 1000 m (3300 ft), and their prime environment appears to be steep ravine-indented slopes along artificial watercourses, with the occasional large dead laurel tree and much tree heath. This species is highly mobile between different areas at different times of year.
It was very abundant when the islands were first colonised by humans, but was extirpated. The losses on the islands were largely due to deforestation for wood and to create agricultural and grazing land.
The exclusion of livestock from the native forest allows it to regenerate and create more suitable habitat. Some illegal hunting and poisoning continues because of the damage this pigeon can do to crops. Perhaps the main limiting factor on the rate at which the pigeon increases its numbers is eggs and young being taken by introduced Black Rats
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
. It is now classed as Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
, an improvement on its Threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
status in 1988. This species is protected under the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
Birds Directive
Birds Directive
The Birds Directive is a European Union directive adopted in 2009. It replaces Council Directive 79/409/EEC of 2 April 1979 on the conservation of wild birds which was modified several times and had become very unclear...
, and the laurel forests under the Habitats Directive.
Taxonomy
The genus ColumbaColumba (genus)
The large bird genus Columba comprises a group of medium to large stout-bodied pigeons, often referred to as the typical pigeons. The terms "dove" and "pigeon" are used indiscriminately for smaller and larger Columbidae, respectively...
is the largest within the pigeon family, and has the widest distribution. Its members are typically pale grey or brown, often with white head or neck markings or iridescent green or purple patches on the neck and breast. The neck feathers may be stiffened and aligned to form grooves. One of several subgroups within Columba consists of the widespread Eurasian Common Wood Pigeon, Bolle's Pigeon, the Trocaz Pigeon, and the African Afep Pigeon
Afep Pigeon
The Afep Pigeon also known as the African Wood-Pigeon, or Gray Wood-Pigeon is a member of the Columbidae family which lives in Africa.Like many other pigeons, it mainly feeds on grain and seeds....
. The two Macaronesia
Macaronesia
Macaronesia is a modern collective name for several groups of islands in the North Atlantic Ocean near Europe and North Africa belonging to three countries: Portugal, Spain, and Cape Verde...
n endemic pigeons, Bolle's and Trocaz, are thought to be derived from isolated island populations of C. palumbus.
The Atlantic archipelagos of the Canaries
Canaries
Canaries may refer to:* Canary Islands, an archipelago in the Atlantic belonging to Spain* Canaries Quarter, a village on the Caribbean island of Saint Lucia* "The Canaries", the nickname of two English football teams: Norwich City F.C. and Hitchin Town F.C....
, Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, and Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...
have a volcanic origin and they have never been part of a continent. The formation of Madeira started in the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
and the island was substantially complete by 700,000 years ago. At various times in the past, the major islands of these archipelagos were all colonised by ancestral wood pigeons, which evolved on their respective islands in isolation from the mainland populations. Mitochondrial
Mitochondrion
In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5 to 1.0 micrometers in diameter...
and nuclear
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
sequences suggest that the ancestor of Bolle's Pigeon may have arrived in the Canaries about 5 mya, but an older lineage that gave rise to another Canarian endemic, the Laurel Pigeon
Laurel Pigeon
The Laurel Pigeon, White-tailed Laurel Pigeon, Paloma rabiche, is a species of bird in the Columba genus in the Columbidae family. It is a member of the family Columbidae of doves and pigeons, which is endemic to the Canary Islands, Spain...
, C. junoniae, may date from 20 mya. The most recent wood pigeon arrival on Macaronesia was that which gave rise to the subspecies C. palumbus maderensis.
The Trocaz Pigeon
Trocaz Pigeon
The Trocaz Pigeon, Madeira Laurel Pigeon or Long-toed Pigeon is a pigeon which is endemic to the island of Madeira. It is a mainly grey bird with a pinkish breast; its silvery neck patch and lack of white wing markings distinguish it from its close relative and probable ancestor, the Common Wood...
was formally described in 1829 by Karl Heineken
Karl Heineken
Karl Heineken , also known as Carlos Heineken, was a German medical doctor and ornithologist. He lived on Madeira, a Portuguese island in Macaronesia, from 1826 until his death. He described the Trocaz Pigeon, a Madeiran endemic bird species...
. He recognised it as different from the now-extinct local form of the Madeiran Wood Pigeon
Madeiran Wood Pigeon
The Madeiran Wood Pigeon was an endemic subspecies of the Wood Pigeon for Madeira . This Wood Pigeon is endemic to the Laurel forest habitat....
a sub-species of the Common Wood Pigeon. This is a monotypic species, although in the past the canarian Bolle's Pigeon was sometimes regarded as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Trocaz Pigeon.