Stresemann's Bush Crow
Encyclopedia
The Stresemann's Bushcrow (Zavattariornis stresemanni), also known as Abyssinian Pie, Bush Crow, Ethiopian Bushcrow, or by its generic name Zavattariornis, is a rather starling
-like bird, which is currently thought to be member of the crow family, Corvidae
, though this is uncertain. It is slightly larger than the North America
n Blue Jay
is a bluish-grey in overall appearance that becomes almost white on the forehead. The throat and chest are creamy-white with the tail and wings a glossy black. The black feather
s have a tendency to bleach to brown at their tips. The iris of the bird is brown and the eye is surrounded by a band of naked bright blue skin. The bill
, legs, and feet are black.
The range of this species is quite restricted being confined to thorn acacia
country in southern Ethiopia
near Yavello (Javello), Mega, and Arero. It can be curiously absent from apparently suitable country near these areas; the reasons for this are not apparent.
Feeding is usually in small groups and takes mainly insect
s. Breeding usually starts in March, with the birds building their nest high in an acacia
tree. The birds usually lay five to six cream eggs
with lilac blotches. The nest
itself is globular in shape with a tubular entrance on top. It is possible that more than just the breeding pair visit the nest and that the young of previous years help in rearing the young.
, a German ornithologist. This species has been placed in several bird families
since its description. It has long been considered a member of the crow family Corvidae
; however, several atypical features, such as its lice being from the suborder Mallophaga, its bare facial skin being capable of movement, and the structure of its palate
, have suggested that it may belong in another family. Some authors placed the species within the starling family Sturnidae due to the bushcrow's similarities in behavior and size with the Wattled Starling
. Other authors have placed it in its own monotypic family, Zavattariornithidae. DNA-sequencing analysis supports its placement in the corvids, with its closest relatives being the ground jay
s, magpies
, and the Piapiac
. It has been suggested that the bushcrow is a surviving relict
ancestor to several of these relatives. However, its taxonomic situation is still considered to be in flux.
This species has numerous common names, including Stresemann's Bushcrow, Bush-crow, Ethiopian Bushcrow, Abyssinian Bushcrow, and Zavattariornis.
decurves into a sharply pointed tip and is relatively small for a corvid. This beak is 33 to 39 mm (1.3 to 1.5 in) long. The feathers on the bird's chin are fine and can form a small tuft when erected. The bushcrow's breast and flanks are pale grey, fading into white on the rear flanks, belly, and undertail. On the wings, the lesser and median upper-wing coverts are grey, while the rest of the wing is a slightly glossy blue-black. Its blue-black tail is relatively long and square-ended. Its legs are black. When the plumage becomes worn, the upperparts appear to have a brownish tinge. The juvenile Stresemann's Bushcrow is slightly duller than the adult, and the feathers of the body and upperwings are fringed with creamy-fawn. The facial skin, bill, and legs are also a dull grey.
The bushcrow is a very vocal species, particularly when foraging. Its main contact call has been described as a single metallic "kej". While flying, the species frequently calls out a nasal, rapid "kerr kerr kerr". While these are the most frequent vocalizations, several others are known. Allopreening adults utter a metallic "kaw, kaw, kaw". Foraging birds call out "how, how, how", a single, quiet "quak", and a soft, repeated "guw". While building its nest, the bushcrow is known to utter a low "keh" sound, and adults utter a deep "waw" while rubbing their bills together.
, Mega
, and Arero
in Sidamo Province
. Its total range covers about 2400 square kilometres (926.6 sq mi).
The Stresemann's Bushcrow lives in flat savanna covered with mature acacia
and Commiphora
thornbushes. The bird prefers open short-grass savannas with scattered stands of these mature thornbushes. The soil must be deep and rich to support the bushcrow. It is most numerous when these stands are next to agricultural fields. For reasons yet unknown, this species can be completely absent from areas of suitable habitat near equally suitable but inhabited land. It is also not found near the scattered broadleaf woodland made up of Combretum
and Terminalia
. It habitat is between 1300 and 1800 m (4,265.1 and 5,905.5 ft) above sea level.
s, Red-billed Hornbill
s, Red-billed Buffalo Weavers, and Superb Starling
s while foraging. When hunting in the trees, it is capable of walking atop horizontal branches and jumping upwards towards the crown, then descending in a glide from the crown to the ground.
It eats primarily invertebrates and specifically insects, including termite
s. Larvae and pupae, especially of Coeloptera
moths, are eaten as well as the adults.
The nest is an untidy globular structure, on which the roof tapers to a point that has an opening into the interior chamber. The nest is 30 centimetres (11.8 in) long and 60 centimetres (23.6 in) in diameter, while the interior chamber is 30 centimetres (11.8 in) in diameter. To start constructing the nest, a single twig is inserted into the top of an acacia
tree 5 to 6 m (16.4 to 19.7 ft) above the ground. This leads to the paired bushcrows becoming excited, engorging their blue facial skin. Almost ritualistically the pair then pick the acacia's leaves and twigs, dropping them to the ground. The pair end this display by chasing each other through the trees before continuing construction. The nest is made out of thorny twigs, which the interior chamber is lined with dry grass and dried cattle dung. Damp soil is used to keep the initial twigs connected. Old nests are repaired and reused.
Up to six eggs are laid in the nest. The bushcrow's eggs are cream-colored with pale lilac blotches that concentrate into a ring at the wider end.
. The rich soil that the species needs to forage is also prime farming land. In the Yabello Wildlife Sanctuary, acacia trees are being collected for firewood, removing the bushcrow's nesting site. While protected under law, this sanctuary has difficulties enforcing the law. It is believed that between 1999 and 2003 the population of the bushcrow declined by 80%.
Starling
Starlings are small to medium-sized passerine birds in the family Sturnidae. The name "Sturnidae" comes from the Latin word for starling, sturnus. Many Asian species, particularly the larger ones, are called mynas, and many African species are known as glossy starlings because of their iridescent...
-like bird, which is currently thought to be member of the crow family, Corvidae
Corvidae
Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, jackdaws, jays, magpies, treepies, choughs and nutcrackers. The common English names used are corvids or the crow family , and there are over 120 species...
, though this is uncertain. It is slightly larger than the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n Blue Jay
Blue Jay
The Blue Jay is a passerine bird in the family Corvidae, native to North America. It is resident through most of eastern and central United States and southern Canada, although western populations may be migratory. It breeds in both deciduous and coniferous forests, and is common near and in...
is a bluish-grey in overall appearance that becomes almost white on the forehead. The throat and chest are creamy-white with the tail and wings a glossy black. The black feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
s have a tendency to bleach to brown at their tips. The iris of the bird is brown and the eye is surrounded by a band of naked bright blue skin. The bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
, legs, and feet are black.
The range of this species is quite restricted being confined to thorn acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
country in southern Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
near Yavello (Javello), Mega, and Arero. It can be curiously absent from apparently suitable country near these areas; the reasons for this are not apparent.
Feeding is usually in small groups and takes mainly insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s. Breeding usually starts in March, with the birds building their nest high in an acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
tree. The birds usually lay five to six cream eggs
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
with lilac blotches. The nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
itself is globular in shape with a tubular entrance on top. It is possible that more than just the breeding pair visit the nest and that the young of previous years help in rearing the young.
Taxonomy
The Stresemann's Bushcrow was described by Edgardo Moltoni in 1938. Its name commemorates Erwin StresemannErwin Stresemann
Erwin Stresemann was a German naturalist and ornithologist.Stresemann was one of the outstanding ornithologists of the 20th century...
, a German ornithologist. This species has been placed in several bird families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
since its description. It has long been considered a member of the crow family Corvidae
Corvidae
Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, jackdaws, jays, magpies, treepies, choughs and nutcrackers. The common English names used are corvids or the crow family , and there are over 120 species...
; however, several atypical features, such as its lice being from the suborder Mallophaga, its bare facial skin being capable of movement, and the structure of its palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...
, have suggested that it may belong in another family. Some authors placed the species within the starling family Sturnidae due to the bushcrow's similarities in behavior and size with the Wattled Starling
Wattled Starling
The Wattled Starling is a nomadic resident in eastern and southern Africa. It is a species of grassland, open woodland and cultivation....
. Other authors have placed it in its own monotypic family, Zavattariornithidae. DNA-sequencing analysis supports its placement in the corvids, with its closest relatives being the ground jay
Ground jay
The ground jays or ground choughs belong to a distinct group of the passerine order of birds in the genus Podoces of the crow family Corvidae...
s, magpies
Pica (genus)
Pica is the genus of two to four species of birds in the family Corvidae in both the New World and the old. They have long tails and have predominantly black and white markings. One species ranges widely from Europe through Asia, one occurs all over North America and the third is restricted to...
, and the Piapiac
Piapiac
The Piapiac is a member of the crow family, and is the only member of the genus Ptilostomus. According to recent findings, it is most closely related to the Central Asian ground jays .-Description:...
. It has been suggested that the bushcrow is a surviving relict
Relict
A relict is a surviving remnant of a natural phenomenon.* In biology a relict is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas....
ancestor to several of these relatives. However, its taxonomic situation is still considered to be in flux.
This species has numerous common names, including Stresemann's Bushcrow, Bush-crow, Ethiopian Bushcrow, Abyssinian Bushcrow, and Zavattariornis.
Description
The Stresemann's Bushcrow is about 28 centimetres (11 in) long and weighs 130 grams (4.6 oz). The genders look similar and are not sexually dimorphic. Overall it is pale grey with a black tail and wings. The head, mantle, scapulars, back, rump, and uppertail coverts are all a pale grey. The feathers on the forehead, upper ear-coverts, and throat fade into white. The bright azure skin around the bushcrow's eye is featherless and can be inflated, narrowing the blackish-brown eye into a slit. The feathers behind the eye are capable of moving to reveal an oblong pink patch of skin. The bird's black beakBeak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
decurves into a sharply pointed tip and is relatively small for a corvid. This beak is 33 to 39 mm (1.3 to 1.5 in) long. The feathers on the bird's chin are fine and can form a small tuft when erected. The bushcrow's breast and flanks are pale grey, fading into white on the rear flanks, belly, and undertail. On the wings, the lesser and median upper-wing coverts are grey, while the rest of the wing is a slightly glossy blue-black. Its blue-black tail is relatively long and square-ended. Its legs are black. When the plumage becomes worn, the upperparts appear to have a brownish tinge. The juvenile Stresemann's Bushcrow is slightly duller than the adult, and the feathers of the body and upperwings are fringed with creamy-fawn. The facial skin, bill, and legs are also a dull grey.
The bushcrow is a very vocal species, particularly when foraging. Its main contact call has been described as a single metallic "kej". While flying, the species frequently calls out a nasal, rapid "kerr kerr kerr". While these are the most frequent vocalizations, several others are known. Allopreening adults utter a metallic "kaw, kaw, kaw". Foraging birds call out "how, how, how", a single, quiet "quak", and a soft, repeated "guw". While building its nest, the bushcrow is known to utter a low "keh" sound, and adults utter a deep "waw" while rubbing their bills together.
Distribution and habitat
This species is endemic to central-southern Ethiopia. It lives in a small area circumscribed by the towns of YabeloYabelo
Yabelo is a town in southern Ethiopia. An alternative name for this town is Obda, which is also the name of a nearby mountain. Located northwest of Moyale in the Guji Zone of the Oromia Region , this town has a latitude and longitude of and an elevation of 1857 meters above sea level...
, Mega
Mega, Ethiopia
Mega is a town in southern Ethiopia. Located between Moyale and Yabelo on the paved highway south to Kenya, in the Borena Zone of the Oromia Region , this town has a latitude and longitude of with an elevation of 1740 meters above sea level...
, and Arero
Arero
Arero is one of the 180 woredas in the Oromia Region of Ethiopia. Part of the Borena Zone, Arero is bordered on the southwest by Dire, on the west by Yabelo, on the north by Hagere Mariam, on the northeast by the Guji Zone, on the east by the Somali Region, and on the south by Moyale; the Dawa...
in Sidamo Province
Sidamo Province
Sidamo was a province in the southern part of Ethiopia, with its capital city at Irgalem, and after 1978 at Awasa. It was named after an ethnic group native to Ethiopia, called the Sidamo, or more particularly, Sidama, who are located in the south-central part of that country...
. Its total range covers about 2400 square kilometres (926.6 sq mi).
The Stresemann's Bushcrow lives in flat savanna covered with mature acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
and Commiphora
Commiphora
Commiphora is a genus of flowering plants in the family Burseraceae. It includes about 185 species of trees and shrubs, often armed or thorny, native to Africa, Arabia, and the Indian subcontinent.-Uses:...
thornbushes. The bird prefers open short-grass savannas with scattered stands of these mature thornbushes. The soil must be deep and rich to support the bushcrow. It is most numerous when these stands are next to agricultural fields. For reasons yet unknown, this species can be completely absent from areas of suitable habitat near equally suitable but inhabited land. It is also not found near the scattered broadleaf woodland made up of Combretum
Combretum
The bushwillows or combretums, Combretum, make up the type genus of the family Combretaceae. The genus comprises about 370 species of trees and shrubs, roughly 300 of which are native to tropical and southern Africa, about 5 to Madagascar, some 25 to tropical Asia and approximately 40 to tropical...
and Terminalia
Terminalia (plant)
Terminalia is a genus of large trees of the flowering plant family Combretaceae, comprising around 100 species distributed in tropical regions of the world. This genus gets it name from Latin terminus, referring to the fact that the leaves appear at the very tips of the shoots.Trees of this genus...
. It habitat is between 1300 and 1800 m (4,265.1 and 5,905.5 ft) above sea level.
Ecology and behavior
The Stresemann's Bushcrow is normally found in groups of about six birds. This species does not migrate.Diet
The bushcrow feeds both on the ground and in trees. It begins foraging at sunrise. While foraging, a bushcrow can be alone, in a pair, or in a group of six or seven other bushcrows. A foraging bushcrow digs vigorously in the soil while its beak is held slightly open to catch any insects it unearths. When it catches something, it carries it to the nearest tree or bush, pins it down with its foot, and kills and eats the prey. This species has also been seen using its beak to tear apart rotten wood and inspecting cattle dung in the search for food. It may also land on the backs of cattle to search for parasites. It can also chase flying insects, which it does on foot, abruptly changing direction and taking flying leaps after its prey. It often mixes with White-crowned StarlingWhite-crowned Starling
The White-crowned Starling is a species of starling in the Sturnidae family.It is found in Djibouti, Ethiopia, Kenya, and Somalia.-References:* BirdLife International 2004. . Downloaded on 24 July 2007....
s, Red-billed Hornbill
Red-billed Hornbill
Red-billed Hornbill is a relatively small species of hornbill found in savanna and woodland of sub-Saharan Africa. It is sometimes split into five species, the Northern Red-billed Hornbill , Western Red-billed Hornbill , Tanzania Red-billed Hornbill , Southern Red-billed Hornbill Red-billed...
s, Red-billed Buffalo Weavers, and Superb Starling
Superb Starling
The Superb Starling is a member of the starling family of birds. It can commonly be found in East Africa, including Ethiopia, Somalia, Uganda, Kenya and Tanzania. Used to be known as Spreo superbus .-Description:...
s while foraging. When hunting in the trees, it is capable of walking atop horizontal branches and jumping upwards towards the crown, then descending in a glide from the crown to the ground.
It eats primarily invertebrates and specifically insects, including termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...
s. Larvae and pupae, especially of Coeloptera
Coeloptera
Coeloptera is a genus of moths belonging to the subfamily Tortricinae of the family Tortricidae.-Species:*Coeloptera epiloma *Coeloptera gyrobathra *Coeloptera vulpina -External links:*...
moths, are eaten as well as the adults.
Reproduction
The Stresemann's Bushcrow nests either alone or in a small, loosely connected colony of three to five nests. It is monogamous and may form a lifelong pair bond. The bushcrow occasionally has a third bird, or in rare cases two to four more, help the breeding couple both build the nest and care for the young. The helpers may also not be restricted to helping one nest at a time, as they have been seen at nests across the loose colonies. Allofeeding and allopreening takes place both between the pair and with the other bushcrows in the colony. The bushcrow lays its eggs shortly after the first rains, which normally occur in late February and early March, leading to its eggs being laid in late March and early April.The nest is an untidy globular structure, on which the roof tapers to a point that has an opening into the interior chamber. The nest is 30 centimetres (11.8 in) long and 60 centimetres (23.6 in) in diameter, while the interior chamber is 30 centimetres (11.8 in) in diameter. To start constructing the nest, a single twig is inserted into the top of an acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
tree 5 to 6 m (16.4 to 19.7 ft) above the ground. This leads to the paired bushcrows becoming excited, engorging their blue facial skin. Almost ritualistically the pair then pick the acacia's leaves and twigs, dropping them to the ground. The pair end this display by chasing each other through the trees before continuing construction. The nest is made out of thorny twigs, which the interior chamber is lined with dry grass and dried cattle dung. Damp soil is used to keep the initial twigs connected. Old nests are repaired and reused.
Up to six eggs are laid in the nest. The bushcrow's eggs are cream-colored with pale lilac blotches that concentrate into a ring at the wider end.
Relationship with humans
Prior to modern settlement in villages, the nomadic indigenous peoples of Ethiopia provided easy hunting grounds for the bushcrow as they left loose, dung-covered soil behind as they moved their cattle. This provided a rich abundance of beetle larvae for the bushcrow to feed upon.Conservation
Changes in the grazing habits of Ethiopia's indigenous peoples following the recent trend of settling in permanent villages have negatively impacted the Stresemann's Bushcrow. While previously grazers left the soil loose and covered in dung to support the bushcrow's prey, this new lifestyle has resulted in overgrazing and soil compaction in some areas. The idea of private land ownership has also led to intensive planting of cash crops such as maizeMaize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
. The rich soil that the species needs to forage is also prime farming land. In the Yabello Wildlife Sanctuary, acacia trees are being collected for firewood, removing the bushcrow's nesting site. While protected under law, this sanctuary has difficulties enforcing the law. It is believed that between 1999 and 2003 the population of the bushcrow declined by 80%.
External links
- Stresemann's Bushcrow from the Internet Bird Collection
- Anthony Disley line drawing of Stresemann's Bushcrow
- BirdLife Species Factsheet
