Tropical Boubou
Encyclopedia
The Tropical Boubou or Bell Shrike (Laniarius aethiopicus) is a medium-sized passerine
bird
of sub-Saharan Africa
. This very diverse "species
" with its numerous subspecies
and morphs has since long posed a taxonomic problem, and recent research suggests it is a cryptic species complex
that ought to be split into several species.
s), measuring 23–25 cm in length. Its weight can vary between about 38-70 g, but typically adults weigh between 50 and 60 g. Females are on average a bit smaller than males, but individual variation is so large that for most practical purposes the sexes seem to be of identical size. The wing measures about 98 mm on average (between 85 and 110), the tail is a mere two millimetres longer both on average and as regards variation. The tarsus
is c.29–37 mm long, 33 mm on average, while the bill's exposed culmen measures a little over 20 mm in some populations and as much as 25 mm in others. Unlike the other measurements where there is mostly individual variation, the bill length might distinctly vary between subspecies
.
Not only are males and females the same size, they have identical plumage too The adults' upperparts and tail are glossy blue-black except for concealed white spots on the rump, visible only when the wings are spread and the rump feathers are erected. The underparts are white, in some populations with a buffy or pinkish tinge on the breast and flanks, which is not always noticeable except in good light. The wings of most subspecies
have a white stripe on the wing coverts, in some extending onto the secondary remiges. The tips of the outer tail feathers can be white in some subspecies. The bill is black, the legs and feet bluish-grey. The irides are dark reddish-brown.
Nestlings have pinkish-brown skin and are nude after hatching, later growing sparse down; they apparently have spots inside their bills which they show their parents to get fed. Fledglings are similar to adults but duller, with the brownish head and the upperparts appearing mottled due to yellowish-ochre to tawny feather tips, forming a barring on the lower back and rump. The wing-stripe, if present, is dulled down. The undertail coverts are buff, and there is usually dusky barring on the dull white underside, especially on the flanks. The bill is greyish-brown above, paler below. Immature birds independent from their parents have lost most of the mottling (except on the wing coverts) and barring, but their wing stripe and underside are still dull white, shading to brown on the flanks; any white tail feather tips appear at this stage.
A melanistic morph
of the taxon
sublacteus occurs in a small area of coastal Kenya
. It is glossy black all over, lacking even the white rump spots.
The northwesternmost populations of major might be confused with Turati's Boubou
(L. turatii), which has no white wing-band and a buff chin and white belly, while major around the southern edge of the Congo Basin
look almost identical to the Swamp Boubou (L. bicolor), but this is pure white below and its females give a characteristic "ratchet
" call in duets. Southeastern birds (mossambicus and especially limpopoensis) resemble the Southern Boubou
(L. ferrugineus) but are black above instead of dark brown and grey – though this may be hard to see at a distance and entirely indistinguishable in the occasionally seen hybrid. The melanistic sublacteus morph is hard to distinguish from the sympatric Slate-coloured Boubou
(L. funebris), but that species is a very dark bluish-grey instead of black. However, even where the "Tropical Boubou" is sympatric with other Laniarius, they are rarely found in the same habitat
.
not a larynx
, in particular many Passeri can sing in two voices at the same time; Tropical Boubous that have lost their mate can make the same sequence that a pair would make. Males probably start most duets, and their notes are mostly low-pitched whistles and/or harsh croaks; females' notes are typically higher whistles and/or "harsh tearing or rattling sounds". But although the birds' vocalizations are somewhat harsh, they are still able of a wide range of frequencies and males provide the higher voice in certain duets.
Duets usually consist of one exchange, two or three calls in total. But up to seven exchanges have been recorded. A duet may be repeated up to 75 times, and in experiments where the birds were confronted with taped vocalizations, they could be enticed to up to 200 duets. A dozen or more duet types exist, and some seem to confer specific information, forming a Morse code
-like sort of language
. Examples of typical duet sequences include hoooooo-ho-ho, hoho-u-ho, hoo-hii-hoo, haw-Weeer-haw, hoou-Weer-hoou, houhou-Weeer and bobobobo-Weeer. During territorial contests of subspecies
major, a wide range of duet types is sung, in particular 1-3 and 9-11. Playback of duet types 1, 2, 9 and perhaps 6 elicits duets of the same type, as well as of others; types 2 and 6 are typically also answered with types 9 and 11, and type 9 with type 3 and perhaps 11.
Duet type 5 of major consists of one to several dozen (typically about 3) short call notes given simultaneously by territorial pairs. Its loud male calls are at about 1.4 kHz, 0.4 second
s and downslurred, while the female calls increase in frequency between 900–1,000 hertz
, are less than half as long, and begin about halfway through the males' calls. After a pair has prevailed in a song contest with an intruder, the birds quieten down for some time and ascertain that the contestant has called it quits; then, they usually move to a prominent perch, the male at the very top with his mate below, and sing duet type 5. This vocalization might be considered a sort of "victory chant", conferring information about the events to neighboring pairs.
Northern birds typically give resonant hooo or hoou whistles, variously short or drawn-out. Among southern birds, grating Weeer and krzzzz calls, snoring Haaw croaks and rattling Ke-Ke-Ke are more common. Other harsh calls, like a metallic Tschanananana or SCHRANG! SCHRANG! are given by the male in aggression and courtship; eastern birds may also give call lit-tuu-iii at the end of a courtship display. Alarm calls are a variety of chattering outbursts; before roosting, birds often make a series of Tuk calls, and they also give a call when the parents change to brood the eggs or young. During social interactions, the wings are often forcefully shaken, producing a ripping mechanical sound.
This species may duet with the Slate-colored Boubou (L. funebris). Trios are common, especially young birds learning to sing tend to join in when a pair duets. Nestlings that want to be fed give high repeated chirps, as usual among passerine
s.
of the Tropical Boubou were recognized – that is, if L. aethiopicus was considered a distinct species at all. As late as the mid-20th century for example, some authors included the entire "Tropical Boubou" complex within L. ferrugineus, which nowadays refers to the Southern Boubou
only.
Recent cladistic analysis of nDNA BRM15 intron
-15 and mtDNA NADH dehydrogenase
subunit
2 and ATP synthase F0 subunit 6 sequence
data indicates that the "Tropical Boubou" as traditionally recognized is a polyphyletic cryptic species complex
, and that three additional species should be recognized. Furthermore, as it seems the "Bulo Burti Boubou
" – described as L liberatus from the only known individual trapped in 1988 – is actually a rare and hitherto unrecognized morph of L. (a.) erlangeri and should be considered its junior synonym.
Contrary to what one might expect in a purely phenetic analysis, the conspicuous variation of wing stripes is no good indicator of relationships among these and related boubou
s. Vocalizations and habitat
preferences, on the other hand, allow a good delimitation of the clades conventionally grouped as "Tropical Boubou". The four proposed species are:
south to the Limpopo River
in South Africa
. In the western part of its range, it is found as a regular breeder from Côte d'Ivoire
eastwards to about 5° N; it is not found further south along the Atlantic coast and in the inner Congo Basin
, but occurs on the Scarp of Angola. It also does not seem to occur in northern Somalia
, eastern Ethiopia
and Kenya
, and central Tanzania
as well as the lower Ruvuma River
basin. It is not a migratory bird and only moves around locally. Seasonal movements are known from Kenya
, while in Ethiopia
they move up the mountains in summer. Vagrants have been recorded from Senegal
, and records from The Gambia
and Liberia
probably are also mostly or all stray birds; a supposed vagrant from Bioko
is not anymore believed to have been of this species.
It is not found in decidedly arid
regions and dense forests such as the equatorial rain forest, but occurs on mountains up to 3,000 m ASL
. It requires dense ground cover, and is found in a variety of forest and forest-edge habitat
s, including savannah
, Miombo woodland and village garden
s. In the drier parts of its range, it is generally restricted to riparian forest
, though the Somali Boubou also utilizes semiarid shrubland. Typical vegetation in its habitat is characterized by such plants as African Juniper (Juniperus procera), bracken
(Pteridium), Rosoideae
shrubs or Brachystegia
.
The birds defend a breeding territory of 1-3 hectars; outside the breeding season they move about in a larger area (up to 8 hectars) and are more tolerant of conspecifics, sometimes assembling into loose noisy groups. They rarely fly long distances and tend to skulk in the shrubs and low in trees like a coucal
(Centropus), or move on the ground interrupted by bouts of wathing where they stand alert, with the tail slightly raised. When alarmed, they will make a slow descending flight, flashing their white rump patches and giving warning calls, before taking cover. As usual for passerine
birds, they scratch indirectly (foot-over-wing). Allopreening has been recorded between mates. At least southern birds moult
their whole plumage after the breeding season. This species is presumably preyed upon by the usual vertebrate
predators of mid-sized birds. A ringed individual nine to ten years old was recorded.
The Tropical Boubou may be common locally, with 100 individuals per square kilometer; in other places only one-third this population density
is recorded however. Still, it is not an uncommon bird across its breeding range and the IUCN treats it as a Species of Least Concern
. When the species is split up, the Somali Boubou and Dimorphic Boubou, which are found only in a limited area, might warrant uplisting.
s (and true shrike
s, Laniidae), the Tropical Boubou impales prey on thorns to eat later; it also wedges prey into crevices.
The food includes many kinds of large terrestrial
invertebrate
s and their larva
e as well as small terrestrial vertebrate
s, e.g. amphibian
s, beetle
s, gecko
s, lizard
s, Lepidoptera
(moths and butterflies), mantis
es, Orthoptera
(crickets, grasshoppers and locusts), rodent
s, snake
s and termite
s. It often plunders other birds' nests and occasionally eats snail
s and fruit
.
is monogamous. The "Tropical Boubou", like many tropical birds, does not have a pronounced breeding season. Around the Equator
, birds may breed at any time in the year. Further north and south, there is a peak breeding season in late spring and early summer at the start of the wet season
, and little to no breeding takes place during late autumn and early winter at the start of the dry season
. Courtship starts with the male chasing the female, the two hopping together through branches, and the male bobbing its head, bowing and giving a croaking call or low whistle. It makes gliding or descending display flights with the white rump spots exposed and producing mechanical noises with its remiges. The courtship climaxes with the male – wings drooped, tail fanned and rump feathers puffed up – giving repeated metallic or whistling calls. The couples may duet, but courtship feeding has not been observed.
The flimsy cup nest is built by both parents, but the female does more of the work. It consists of twigs, tendrils, small roots and the occasional grass
leaf or bark
piece, held together with spider web
and sometimes lined with finer fibres; the walls are thick – more than one to more than 5 cm – but loosely constructed and the eggs can often be seen from the outside. The nest measures 10 to 20 cm in diameter, with a shallow nest cup around 8 cm in diameter and 2–5 cm deep. It is placed at varying heights, from a few dozen cm above ground in a thicket to more than a dozen meters up in a tree top; typically however its is built around 3 m in a bush, a horizontal branch fork, or in vines. Nesting sites are often solitary bushes, which provide cover while allowing the incubating bird to observe the surrounding terrain for threats.
The female lays three, sometimes two eggs, which are bluish to buffy green with brown and lilac spots and measure around 22-27 by 17–19 mm, or about 25 by 18.3 mm on average. Both parents incubate, but the female does most of the work. The eggs hatch after 14–16 days, and nestlings take again as long to fledge
. The parents usually destroy the nest after the young have left it. They continue to feed their offspring for about seven more weeks, after which the young can forage on their own. They stay with their parents for about five months.
The Black Cuckoo
(Cuculus clamosus) is a common brood parasite
of this boubou
, parasitizing about 2% of its nests. When Tropical Boubous spot Black Cuckoos, they usually try to mob
them away and are often successful in this; some pairs however seem to be very inept at preventing brood parasitism and may be affected several times per year.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
of sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
. This very diverse "species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
" with its numerous 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...
and morphs has since long posed a taxonomic problem, and recent research suggests it is a cryptic species complex
Cryptic species complex
In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each other—but whose morphology is very similar ....
that ought to be split into several species.
Description
The Tropical Boubou is fairly large for its family (bushshrikeBushshrike
The bushshrikes are smallish passerine bird species. They were formerly classed with the true shrikes in the family Laniidae, but are now considered sufficiently distinctive to be separated from that group as the family Malaconotidae....
s), measuring 23–25 cm in length. Its weight can vary between about 38-70 g, but typically adults weigh between 50 and 60 g. Females are on average a bit smaller than males, but individual variation is so large that for most practical purposes the sexes seem to be of identical size. The wing measures about 98 mm on average (between 85 and 110), the tail is a mere two millimetres longer both on average and as regards variation. The tarsus
Tarsus (skeleton)
In tetrapods, the tarsus is a cluster of articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. In the foot the tarsus articulates with the bones of the metatarsus, which in turn articulate with the bones of the individual toes...
is c.29–37 mm long, 33 mm on average, while the bill's exposed culmen measures a little over 20 mm in some populations and as much as 25 mm in others. Unlike the other measurements where there is mostly individual variation, the bill length might distinctly vary between 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...
.
Not only are males and females the same size, they have identical plumage too The adults' upperparts and tail are glossy blue-black except for concealed white spots on the rump, visible only when the wings are spread and the rump feathers are erected. The underparts are white, in some populations with a buffy or pinkish tinge on the breast and flanks, which is not always noticeable except in good light. The wings of most 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...
have a white stripe on the wing coverts, in some extending onto the secondary remiges. The tips of the outer tail feathers can be white in some subspecies. The bill is black, the legs and feet bluish-grey. The irides are dark reddish-brown.
Nestlings have pinkish-brown skin and are nude after hatching, later growing sparse down; they apparently have spots inside their bills which they show their parents to get fed. Fledglings are similar to adults but duller, with the brownish head and the upperparts appearing mottled due to yellowish-ochre to tawny feather tips, forming a barring on the lower back and rump. The wing-stripe, if present, is dulled down. The undertail coverts are buff, and there is usually dusky barring on the dull white underside, especially on the flanks. The bill is greyish-brown above, paler below. Immature birds independent from their parents have lost most of the mottling (except on the wing coverts) and barring, but their wing stripe and underside are still dull white, shading to brown on the flanks; any white tail feather tips appear at this stage.
A melanistic morph
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
of the taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
sublacteus occurs in a small area of coastal Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
. It is glossy black all over, lacking even the white rump spots.
The northwesternmost populations of major might be confused with Turati's Boubou
Turati's Boubou
The Turati's Boubou is a species of bird in the Malaconotidae family.It is found in Guinea, Guinea-Bissau, and Sierra Leone.Its natural habitat is moist savanna.-References:...
(L. turatii), which has no white wing-band and a buff chin and white belly, while major around the southern edge of the Congo Basin
Congo Basin
The Congo Basin is the sedimentary basin that is the drainage of the Congo River of west equatorial Africa. The basin begins in the highlands of the East African Rift system with input from the Chambeshi River, the Uele and Ubangi Rivers in the upper reaches and the Lualaba River draining wetlands...
look almost identical to the Swamp Boubou (L. bicolor), but this is pure white below and its females give a characteristic "ratchet
Ratchet (device)
A ratchet is a device that allows continuous linear or rotary motion in only one direction while preventing motion in the opposite direction. Because most socket wrenches today use ratcheting handles, the term "ratchet" alone is often used to refer to a ratcheting wrench, and the terms "ratchet"...
" call in duets. Southeastern birds (mossambicus and especially limpopoensis) resemble the Southern Boubou
Southern Boubou
The Southern Boubou is a bushshrike. This family of passerine birds is closely related to the true shrikes in the family Laniidae, and were once included in that group....
(L. ferrugineus) but are black above instead of dark brown and grey – though this may be hard to see at a distance and entirely indistinguishable in the occasionally seen hybrid. The melanistic sublacteus morph is hard to distinguish from the sympatric Slate-coloured Boubou
Slate-coloured Boubou
The Slate-coloured Boubou is a species of bird in the Malaconotidae family. It is found in Ethiopia, Kenya, Rwanda, Somalia, Sudan, Tanzania, and Uganda. Its natural habitats are subtropical or tropical dry forests, dry savanna, subtropical or tropical dry shrubland, and subtropical or tropical...
(L. funebris), but that species is a very dark bluish-grey instead of black. However, even where the "Tropical Boubou" is sympatric with other Laniarius, they are rarely found in the same habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
.
Voice
This species is heard more often than seen, but its calls often help to locate it visually. To vocalize they move higher off the ground than during their usual activities, and may perch on an exposed site. They also nod their head and bow their body when calling, making them even conspicuous sometimes. Calls like bou, hou or boubou give the bird its name; they may be extended into a bubbling bobobobo and are given loudly and higher-pitched to announce the birds' presence, or lower and softer by foraging groups to maintain contact. Like many bush-shrikes, it has a wide vocal repertoire that includes duets in which two individuals – a male-female pair or two males with adjacent territories – give notes alternately in so rapid a sequence that they sound like one bird. As the voicebox of birds is a syrinxSyrinx (biology)
Syrinx is the name for the vocal organ of birds. Located at the base of a bird's trachea, it produces sounds without the vocal cords of mammals. The sound is produced by vibrations of some or all of the membrana tympaniformis and the pessulus caused by air flowing through the syrinx...
not a larynx
Larynx
The larynx , commonly called the voice box, is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume...
, in particular many Passeri can sing in two voices at the same time; Tropical Boubous that have lost their mate can make the same sequence that a pair would make. Males probably start most duets, and their notes are mostly low-pitched whistles and/or harsh croaks; females' notes are typically higher whistles and/or "harsh tearing or rattling sounds". But although the birds' vocalizations are somewhat harsh, they are still able of a wide range of frequencies and males provide the higher voice in certain duets.
Duets usually consist of one exchange, two or three calls in total. But up to seven exchanges have been recorded. A duet may be repeated up to 75 times, and in experiments where the birds were confronted with taped vocalizations, they could be enticed to up to 200 duets. A dozen or more duet types exist, and some seem to confer specific information, forming a Morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
-like sort of language
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
. Examples of typical duet sequences include hoooooo-ho-ho, hoho-u-ho, hoo-hii-hoo, haw-Weeer-haw, hoou-Weer-hoou, houhou-Weeer and bobobobo-Weeer. During territorial contests of 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...
major, a wide range of duet types is sung, in particular 1-3 and 9-11. Playback of duet types 1, 2, 9 and perhaps 6 elicits duets of the same type, as well as of others; types 2 and 6 are typically also answered with types 9 and 11, and type 9 with type 3 and perhaps 11.
Duet type 5 of major consists of one to several dozen (typically about 3) short call notes given simultaneously by territorial pairs. Its loud male calls are at about 1.4 kHz, 0.4 second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s and downslurred, while the female calls increase in frequency between 900–1,000 hertz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
, are less than half as long, and begin about halfway through the males' calls. After a pair has prevailed in a song contest with an intruder, the birds quieten down for some time and ascertain that the contestant has called it quits; then, they usually move to a prominent perch, the male at the very top with his mate below, and sing duet type 5. This vocalization might be considered a sort of "victory chant", conferring information about the events to neighboring pairs.
Northern birds typically give resonant hooo or hoou whistles, variously short or drawn-out. Among southern birds, grating Weeer and krzzzz calls, snoring Haaw croaks and rattling Ke-Ke-Ke are more common. Other harsh calls, like a metallic Tschanananana or SCHRANG! SCHRANG! are given by the male in aggression and courtship; eastern birds may also give call lit-tuu-iii at the end of a courtship display. Alarm calls are a variety of chattering outbursts; before roosting, birds often make a series of Tuk calls, and they also give a call when the parents change to brood the eggs or young. During social interactions, the wings are often forcefully shaken, producing a ripping mechanical sound.
This species may duet with the Slate-colored Boubou (L. funebris). Trios are common, especially young birds learning to sing tend to join in when a pair duets. Nestlings that want to be fed give high repeated chirps, as usual among passerine
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
s.
Taxonomy and systematics
Traditionally, seven subspeciesSubspecies
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 Tropical Boubou were recognized – that is, if L. aethiopicus was considered a distinct species at all. As late as the mid-20th century for example, some authors included the entire "Tropical Boubou" complex within L. ferrugineus, which nowadays refers to the Southern Boubou
Southern Boubou
The Southern Boubou is a bushshrike. This family of passerine birds is closely related to the true shrikes in the family Laniidae, and were once included in that group....
only.
Recent cladistic analysis of nDNA BRM15 intron
Intron
An intron is any nucleotide sequence within a gene that is removed by RNA splicing to generate the final mature RNA product of a gene. The term intron refers to both the DNA sequence within a gene, and the corresponding sequence in RNA transcripts. Sequences that are joined together in the final...
-15 and mtDNA NADH dehydrogenase
NADH dehydrogenase
NADH dehydrogenase is an enzyme located in the inner mitochondrial membrane that catalyzes the transfer of electrons from NADH to coenzyme Q...
subunit
Protein subunit
In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles with other protein molecules to form a protein complex: a multimeric or oligomeric protein. Many naturally occurring proteins and enzymes are multimeric...
2 and ATP synthase F0 subunit 6 sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data indicates that the "Tropical Boubou" as traditionally recognized is a polyphyletic cryptic species complex
Cryptic species complex
In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each other—but whose morphology is very similar ....
, and that three additional species should be recognized. Furthermore, as it seems the "Bulo Burti Boubou
Bulo Burti Boubou
The Somali Boubou is a medium-size bushshrike. It was split from the Tropical Boubou as a result of DNA sequence analysis, and this change in status was recognized by the International Ornithological Committee in 2008...
" – described as L liberatus from the only known individual trapped in 1988 – is actually a rare and hitherto unrecognized morph of L. (a.) erlangeri and should be considered its junior synonym.
Contrary to what one might expect in a purely phenetic analysis, the conspicuous variation of wing stripes is no good indicator of relationships among these and related boubou
Laniarius
Laniarius is a genus of brightly coloured, carnivorous passerine birds commonly known as boubous or gonoleks. Not to be confused with the similar-sounding genus Lanius, they were formerly classed with the true shrikes in the family Laniidae, but they and related genera are now considered...
s. Vocalizations and habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
preferences, on the other hand, allow a good delimitation of the clades conventionally grouped as "Tropical Boubou". The four proposed species are:
- Somali Boubou, L. erlangeri – S SomaliaSomaliaSomalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...
. Includes L. liberatus
- Outer tail feathers never have white tips. Short wings stripe across the median coverts. Breast and belly pinkish. The liberatus morph has long white wing stripe like aethiopicus, and a yellowish-buff chin to chest and superciliumSuperciliumThe supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...
.- A quite ancient lineage, part of a rather basal group of mostly allopatric relictRelictA 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....
forms – the dark-bellied Mountain BoubouMountain BoubouThe Mountain Boubou is a species of bird in the Malaconotidae family.It is found in Burundi, Cameroon, Democratic Republic of the Congo, Equatorial Guinea, Nigeria, Rwanda, and Uganda.-References:...
(L. poensis), Fuelleborn's BoubouFuelleborn's BoubouThe Fuelleborn's Boubou is a species of bird in the Malaconotidae family.It is found in Malawi, Tanzania, and Zambia.The name of this bird commemorates the German physician Friedrich Fülleborn.-References:...
(L. fuelleborni) and perhaps Slate-coloured BoubouSlate-coloured BoubouThe Slate-coloured Boubou is a species of bird in the Malaconotidae family. It is found in Ethiopia, Kenya, Rwanda, Somalia, Sudan, Tanzania, and Uganda. Its natural habitats are subtropical or tropical dry forests, dry savanna, subtropical or tropical dry shrubland, and subtropical or tropical...
(L. funebris), and the sympatric light-bellied Red-naped Boubou (L. ruficeps) to which it might be closest. The western members of this group inhabit montane forest, the others dry shrubland. The liberatus morph may be an atavismAtavismAtavism is the tendency to revert to ancestral type. In biology, an atavism is an evolutionary throwback, such as traits reappearing which had disappeared generations before. Atavisms can occur in several ways...
of plesiomorphic alleleAlleleAn allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
s retained from a common ancestor with L. ruficeps, as the type specimen showed no indication of recent hybridization whatsoever.- Dimorphic Boubou or East Coast Boubou, L. sublacteus – Coastal Kenya, ZanzibarZanzibarZanzibar ,Persian: زنگبار, from suffix bār: "coast" and Zangi: "bruin" ; is a semi-autonomous part of Tanzania, in East Africa. It comprises the Zanzibar Archipelago in the Indian Ocean, off the coast of the mainland, and consists of numerous small islands and two large ones: Unguja , and Pemba...
- Dimorphic Boubou or East Coast Boubou, L. sublacteus – Coastal Kenya, Zanzibar
- A quite ancient lineage, part of a rather basal group of mostly allopatric relict
- Vestigial or no white wing stripe. Outer tail feathers may have white tips. Juveniles have no barring on underside. An all-black morph occurs in the area around the lower JubbaJubba RiverThe Jubba River is a river in southern Somalia. It begins at the border with Ethiopia, where the Dawa and Ganale Dorya rivers meet, and flows directly south to the Indian Ocean, where it empties at the Goobweyn juncture.-History:...
and Tana RiverTana River (Kenya)The long Tana River is the longest river in Kenya, and gives its name to the Tana River District. Its tributaries include the Thika. The river rises in the Aberdare Mountains to the west of Nyeri. Initially it runs east before turning south around the massif of Mount Kenya. The river then runs...
s and on the Lamu Archipelago.- Ethiopian Boubou, L. aethiopicus – E SudanSudanSudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...
through DjiboutiDjiboutiDjibouti , officially the Republic of Djibouti , is a country in the Horn of Africa. It is bordered by Eritrea in the north, Ethiopia in the west and south, and Somalia in the southeast. The remainder of the border is formed by the Red Sea and the Gulf of Aden at the east...
, EritreaEritreaEritrea , officially the State of Eritrea, is a country in the Horn of Africa. Eritrea derives it's name from the Greek word Erethria, meaning 'red land'. The capital is Asmara. It is bordered by Sudan in the west, Ethiopia in the south, and Djibouti in the southeast...
, EthiopiaEthiopiaEthiopia , 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...
and W SomaliaSomaliaSomalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...
to N KenyaKenyaKenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
- Ethiopian Boubou, L. aethiopicus – E Sudan
- Breast and belly pinkish. Narrow wing stripe, extending across the median and larger wing coverts, and often a bit onto the secondary remiges. Outer tail feathers never have white tips.
- West African Boubou (Tropical Boubou in the strict sense), L. major – Sierra LeoneSierra LeoneSierra Leone , officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of and has an estimated population between 5.4 and 6.4...
east to SudanSudanSudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...
, then south to the Great LakesAfrican Great LakesThe African Great Lakes are a series of lakes and the Rift Valley lakes in and around the geographic Great Rift Valley formed by the action of the tectonic East African Rift on the continent of Africa...
region, from there excluding the inner Congo basinCongo BasinThe Congo Basin is the sedimentary basin that is the drainage of the Congo River of west equatorial Africa. The basin begins in the highlands of the East African Rift system with input from the Chambeshi River, the Uele and Ubangi Rivers in the upper reaches and the Lualaba River draining wetlands...
southwest to the Scarp of Angola. Intergrades with mossambicus in the southeastern Congo Basin. Possibly hybridizes with Swamp Boubou (L. bicolor) in the AngolaAngolaAngola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...
region.- L. m. ambiguus – Highlands of Kenya and NE TanzaniaTanzaniaThe United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
- L. m. ambiguus – Highlands of Kenya and NE Tanzania
- In major, long narrow wing stripe across the median and larger wing coverts, and usually continuing onto the secondary remiges; breast and belly may be pinkish (particularly in northern birds) or off-white (as in most southern birds). In ambiguus, short wings stripe across the median coverts; breast and belly pinkish. Outer tail feathers may have white tips in both subspecies.
- L. "a." mossambicus – S Democratic Republic of the CongoDemocratic Republic of the CongoThe Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...
, E ZambiaZambiaZambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....
, E MozambiqueMozambiqueMozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
. Intergrades with major in the southeastern Congo Basin.
- L. "a." mossambicus – S Democratic Republic of the Congo
- Smaller and buffier below than the northern populations. Long narrow wing stripe like in major. Outer tail feathers never have white tips.
- L. "a." limpopoensis – W Mozambique to S ZimbabweZimbabweZimbabwe is a landlocked country located in the southern part of the African continent, between the Zambezi and Limpopo rivers. It is bordered by South Africa to the south, Botswana to the southwest, Zambia and a tip of Namibia to the northwest and Mozambique to the east. Zimbabwe has three...
and N South AfricaSouth AfricaThe Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. Hybridizes with Southern BoubouSouthern BoubouThe Southern Boubou is a bushshrike. This family of passerine birds is closely related to the true shrikes in the family Laniidae, and were once included in that group....
(L. ferrugineus) in LimpopoLimpopoLimpopo is the northernmost province of South Africa. The capital is Polokwane, formerly named Pietersburg. The province was formed from the northern region of Transvaal Province in 1994, and initially named Northern Transvaal...
valley.
- L. "a." limpopoensis – W Mozambique to S Zimbabwe
- The buffiest of all, without pink tones. Long narrow wing stripe like in major. Outer tail feathers never have white tips.
- These seem to be part of a close-knit and more apomorphic cladeCladeA clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of parapatric to sympatric black-and-white (or -buff/-pinkish) boubous which mostly inhabit semihumid lowland habitat. Their relatives are Turati's BoubouTurati's BoubouThe Turati's Boubou is a species of bird in the Malaconotidae family.It is found in Guinea, Guinea-Bissau, and Sierra Leone.Its natural habitat is moist savanna.-References:...
(L. turatii) and perhaps Luehder's Bushshrike (L. luehderi), and the Southern and Swamp Boubous. L. sublacteus seems to form a distinct southern lineage with the last two, but the southernmost "Tropical Boubous" are too little studied. It seems certain that they belong to the second group, where they may be a southward extension of L. aethiopicus, but more likely represent the southwestern populations of L. major. The hybridization is liable to confound DNA sequence analyses, particularly of mtDNA.
- These seem to be part of a close-knit and more apomorphic clade
Range and ecology
The "Tropical Boubou" occurs from about 10° northern latitudeLatitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
south to the Limpopo River
Limpopo River
The Limpopo River rises in central southern Africa, and flows generally eastwards to the Indian Ocean. It is around long, with a drainage basin in size. Its mean annual discharge is 170 m³/s at its mouth...
in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. In the western part of its range, it is found as a regular breeder from Côte d'Ivoire
Côte d'Ivoire
The Republic of Côte d'Ivoire or Ivory Coast is a country in West Africa. It has an area of , and borders the countries Liberia, Guinea, Mali, Burkina Faso and Ghana; its southern boundary is along the Gulf of Guinea. The country's population was 15,366,672 in 1998 and was estimated to be...
eastwards to about 5° N; it is not found further south along the Atlantic coast and in the inner Congo Basin
Congo Basin
The Congo Basin is the sedimentary basin that is the drainage of the Congo River of west equatorial Africa. The basin begins in the highlands of the East African Rift system with input from the Chambeshi River, the Uele and Ubangi Rivers in the upper reaches and the Lualaba River draining wetlands...
, but occurs on the Scarp of Angola. It also does not seem to occur in northern Somalia
Somalia
Somalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...
, eastern 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...
and Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, and central Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
as well as the lower Ruvuma River
Ruvuma River
Ruvuma River, formerly also known as the Rovuma River, is a river in East Africa, forming during the greater part of its course the border between Tanzania and Mozambique . It is long, with a drainage basin in size...
basin. It is not a migratory bird and only moves around locally. Seasonal movements are known from Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, while in 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...
they move up the mountains in summer. Vagrants have been recorded from Senegal
Senegal
Senegal , officially the Republic of Senegal , is a country in western Africa. It owes its name to the Sénégal River that borders it to the east and north...
, and records from The Gambia
The Gambia
The Republic of The Gambia, commonly referred to as The Gambia, or Gambia , is a country in West Africa. Gambia is the smallest country on mainland Africa, surrounded by Senegal except for a short coastline on the Atlantic Ocean in the west....
and Liberia
Liberia
Liberia , officially the Republic of Liberia, is a country in West Africa. It is bordered by Sierra Leone on the west, Guinea on the north and Côte d'Ivoire on the east. Liberia's coastline is composed of mostly mangrove forests while the more sparsely populated inland consists of forests that open...
probably are also mostly or all stray birds; a supposed vagrant from Bioko
Bioko
Bioko is an island 32 km off the west coast of Africa, specifically Cameroon, in the Gulf of Guinea. It is the northernmost part of Equatorial Guinea with a population of 124,000 and an area of . It is volcanic with its highest peak the Pico Basile at .-Geography:Bioko has a total area of...
is not anymore believed to have been of this species.
It is not found in decidedly arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
regions and dense forests such as the equatorial rain forest, but occurs on mountains up to 3,000 m ASL
Above mean sea level
The term above mean sea level refers to the elevation or altitude of any object, relative to the average sea level datum. AMSL is used extensively in radio by engineers to determine the coverage area a station will be able to reach...
. It requires dense ground cover, and is found in a variety of forest and forest-edge habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s, including savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
, Miombo woodland and village garden
Garden
A garden is a planned space, usually outdoors, set aside for the display, cultivation, and enjoyment of plants and other forms of nature. The garden can incorporate both natural and man-made materials. The most common form today is known as a residential garden, but the term garden has...
s. In the drier parts of its range, it is generally restricted to riparian forest
Riparian forest
A riparian forest is a forested area of land adjacent to a body of water such as a river, stream, pond, lake, marshland, estuary, canal, sink or reservoir. -Etymology:...
, though the Somali Boubou also utilizes semiarid shrubland. Typical vegetation in its habitat is characterized by such plants as African Juniper (Juniperus procera), bracken
Bracken
Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...
(Pteridium), Rosoideae
Rosoideae
The rose subfamily Rosoideae consists of more than 850 species, including many shrubs, perennial herbs, and fruit plants such as strawberries and brambles...
shrubs or Brachystegia
Brachystegia
Brachystegia is a genus of tree of the sub-family Caesalpinioideae that is native to tropical Africa. Trees of the genus are commonly known as Miombo, and are the predominant tree in the Miombo woodlands of central and southern Africa.-Species:...
.
The birds defend a breeding territory of 1-3 hectars; outside the breeding season they move about in a larger area (up to 8 hectars) and are more tolerant of conspecifics, sometimes assembling into loose noisy groups. They rarely fly long distances and tend to skulk in the shrubs and low in trees like a coucal
Coucal
A coucal is one of about 30 species of birds in the cuckoo family. All of them belong in the subfamily Centropodinae and the genus Centropus. Unlike many Old World cuckoos, coucals are not brood parasites...
(Centropus), or move on the ground interrupted by bouts of wathing where they stand alert, with the tail slightly raised. When alarmed, they will make a slow descending flight, flashing their white rump patches and giving warning calls, before taking cover. As usual for passerine
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
birds, they scratch indirectly (foot-over-wing). Allopreening has been recorded between mates. At least southern birds moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
their whole plumage after the breeding season. This species is presumably preyed upon by the usual vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
predators of mid-sized birds. A ringed individual nine to ten years old was recorded.
The Tropical Boubou may be common locally, with 100 individuals per square kilometer; in other places only one-third this population density
Population density
Population density is a measurement of population per unit area or unit volume. It is frequently applied to living organisms, and particularly to humans...
is recorded however. Still, it is not an uncommon bird across its breeding range and the IUCN treats it as a Species of Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
. When the species is split up, the Somali Boubou and Dimorphic Boubou, which are found only in a limited area, might warrant uplisting.
Food and feeding
It usually forages on or near the ground, and does not ascend to the tree canopy often. It holds large prey down with its foot while eating. Like other bushshrikeBushshrike
The bushshrikes are smallish passerine bird species. They were formerly classed with the true shrikes in the family Laniidae, but are now considered sufficiently distinctive to be separated from that group as the family Malaconotidae....
s (and true shrike
Shrike
Shrikes are passerine birds of the family Laniidae. The family is composed of thirty-one species in three genera. The family name, and that of the largest genus, Lanius, is derived from the Latin word for "butcher", and some shrikes were also known as "butcher birds" because of their feeding habits...
s, Laniidae), the Tropical Boubou impales prey on thorns to eat later; it also wedges prey into crevices.
The food includes many kinds of large terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s and their larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e as well as small terrestrial vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s, e.g. amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s, beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s, gecko
Gecko
Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 cm to 60 cm....
s, lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s, Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
(moths and butterflies), mantis
Mantis
Mantis is the common name of any insect in the order Mantodea, also commonly known as praying mantises. The word itself means "prophet" in Latin and Greek...
es, Orthoptera
Orthoptera
Orthoptera is an order of insects with paurometabolous or incomplete metamorphosis, including the grasshoppers, crickets and locusts.Many insects in this order produce sound by rubbing their wings against each other or their legs, the wings or legs containing rows of corrugated bumps...
(crickets, grasshoppers and locusts), rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s, snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s and 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. It often plunders other birds' nests and occasionally eats snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s and fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
.
Reproduction
This speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
is monogamous. The "Tropical Boubou", like many tropical birds, does not have a pronounced breeding season. Around the Equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
, birds may breed at any time in the year. Further north and south, there is a peak breeding season in late spring and early summer at the start of the wet season
Wet season
The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
, and little to no breeding takes place during late autumn and early winter at the start of the dry season
Dry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
. Courtship starts with the male chasing the female, the two hopping together through branches, and the male bobbing its head, bowing and giving a croaking call or low whistle. It makes gliding or descending display flights with the white rump spots exposed and producing mechanical noises with its remiges. The courtship climaxes with the male – wings drooped, tail fanned and rump feathers puffed up – giving repeated metallic or whistling calls. The couples may duet, but courtship feeding has not been observed.
The flimsy cup nest is built by both parents, but the female does more of the work. It consists of twigs, tendrils, small roots and the occasional grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
leaf or bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
piece, held together with spider web
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....
and sometimes lined with finer fibres; the walls are thick – more than one to more than 5 cm – but loosely constructed and the eggs can often be seen from the outside. The nest measures 10 to 20 cm in diameter, with a shallow nest cup around 8 cm in diameter and 2–5 cm deep. It is placed at varying heights, from a few dozen cm above ground in a thicket to more than a dozen meters up in a tree top; typically however its is built around 3 m in a bush, a horizontal branch fork, or in vines. Nesting sites are often solitary bushes, which provide cover while allowing the incubating bird to observe the surrounding terrain for threats.
The female lays three, sometimes two eggs, which are bluish to buffy green with brown and lilac spots and measure around 22-27 by 17–19 mm, or about 25 by 18.3 mm on average. Both parents incubate, but the female does most of the work. The eggs hatch after 14–16 days, and nestlings take again as long to fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
. The parents usually destroy the nest after the young have left it. They continue to feed their offspring for about seven more weeks, after which the young can forage on their own. They stay with their parents for about five months.
The Black Cuckoo
Black Cuckoo
The Black Cuckoo is a species of cuckoo in the Cuculidae family. The species is distributed widely across sub-Saharan Africa...
(Cuculus clamosus) is a common brood parasite
Brood parasite
Brood parasites are organisms that use the strategy of brood parasitism, a kind of kleptoparasitism found among birds, fish or insects, involving the manipulation and use of host individuals either of the same or different species to raise the young of the brood-parasite...
of this boubou
Laniarius
Laniarius is a genus of brightly coloured, carnivorous passerine birds commonly known as boubous or gonoleks. Not to be confused with the similar-sounding genus Lanius, they were formerly classed with the true shrikes in the family Laniidae, but they and related genera are now considered...
, parasitizing about 2% of its nests. When Tropical Boubous spot Black Cuckoos, they usually try to mob
Mobbing behavior
Mobbing in animals is an antipredator behavior which occurs when individuals of a certain species mob a predator by cooperatively attacking or harassing it, usually to protect their offspring. A simple definition of mobbing is an assemblage of individuals around a potentially dangerous predator...
them away and are often successful in this; some pairs however seem to be very inept at preventing brood parasitism and may be affected several times per year.