Bush-shrikes are generally seen singly or in pairs, but small parties, probably family groups, have been recorded. They appear to be monogamous and territorial, but very little is known about the social organization of many species, as their tendency to keep to thick cover makes them difficult to observe. One of the easiest to spot is the beautiful, long-tailed, rosy-patched shrike (Tchagra cruentus), which lives in dry bush areas in eastern Africa. Its noisy family groups are constantly active, flying low or hopping on the ground. Members of a pair may be conspicuous in breeding time, when they project their melodious whistles from the top of a bush. Song is an important means of communication in tropical forests or dense shrub and often betrays the presence of bush-shrikes. Malaconotus species project many sounds, including distinctive, far-carrying whistles and bell-like phrases. Laniarius are well-known for their extraordinary duet-songs; what appears to be the call of a single bird is often a kind of whistle by the male immediately followed by generally harsher notes by the female. The brubru bears its name well; its call is onomatopoeic and recalls the trilling song of the male. Some tcha-gras produce clear lilting, melodious, almost human-sounding
phrases that may accompany typical display flights. These displays start with a steep climb, during which the wings are extended and the tail is fanned out, and they end with a gliding descent. The puffbacks may be seen for a few seconds during their short butterfly flights, made with their puff expanded. Most bush-shrikes are apparently sedentary, although local movements are obvious in a few species. Altitudinal movements have been recorded in the olive bush-shrike (Telopho-rus olivaceus) in Malawi and Zimbabwe.
Helmet-shrikes are easier to observe; they are highly sociable with up to 30 birds in a single group; they forage and roost communally and breed cooperatively, with each group under the dominance of the only breeding female. Most species have local or altitudinal movements.
Two African true shrikes are gregarious: the long-tailed fiscal (L. cabanisi) and the gray-backed fiscal (L. excubitoroides). The latter, and possibly also the former, breed cooperatively, with only one breeding pair that benefits from the presence of a varying number of helpers. All the other species are found singly or in solitary pairs. However, loose colonies are known, particularly in the case of the lesser gray shrike (L. minor), and concentrations may also occur during migration. All La-nius are normally monogamous; that, however, does not exclude extra pair paternity, which has been proven in at least three species. They are also highly territorial, with territories covering on average 3.7 acres (1.5 ha) in the small red-backed shrike and up to 250 acres (100 ha) or more in the much larger northern shrike. In many Lanius species, songs are relatively rare and not far-carrying, although territorial calls are important. Almost all or all Lanius shrikes impale their prey, but the regularity of this behavior varies between and even within species. Pair formation takes place inside the territory, display-flights are known in some species, and curious group meetings have been recorded in the northern shrike and in the loggerhead shrike. Courtship feeding is regular. Depending on latitude and feeding habits, Lanius species can be resident; or partial, altitudinal, or long-distance migrants. African species are probably sedentary, while some populations of the
Eurasian red-backed and lesser gray shrikes may travel 6,200 mi (10,000 km) or more.
Was this article helpful?