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Description
The Black-crowned Tchagra (Tchagra senegalus)species are found in the ranges throughout the more humid parts of Africa in the scrub, open woodland, semi-desert, and cultivations.
Range
This bush-shrike is a passerine bird that has been recorded in northern Namibia, Botswana, Zimbabwe, the Transvaal, Swaziland, KwaZulu-Natal, and the Eastern Cape Province.
The four subspecies in the region appear to have continuous ranges, except for a break of lower reporting rates through the Transvaal which probably separates T. s. Kalahari in the west from the race Mozambique to the east. Its density has been estimated at 1 pair/25 ha at Nylsvlei but the size of a breeding territory may be 4 ha.
It is usually encountered in pairs. Although it remains hidden in the foliage much of the time, it is extremely vocal and its presence is easily detected by observers who are familiar with its distinctive calls. Confusion with the similar-looking Southern Tchagra T. tchagra and Three-streaked Tchagra T. australis is possible.
Habitat
It is present in a wide range of scrub and woodland habitats (avoiding the more arid regions with an average annual rainfall below 300 mm) and occurs within exotic timber plantations, but only where dense undergrowth is present. The vegetation analysis shows that, although it is present in most woodland types, it is most common in mesic, broadleaved woodlands such as Miombo and Moist Woodland, and is considerably less common in Mopane and Valley Bushveld.
Although a fairly high re-porting rate is shown for forest biomes, it is found only in the fringes and surrounding areas rather than in the forest interior. Similarly, it is found only in thickets and patches of alien trees in the grassland biome. It is common in large gardens and parks.
Movements
It is suspected of undertaking some short-range seasonal movements but the resolution of the atlas data is too coarse to reveal positive evidence of such minor movements. The models show that it was reported more frequently in the summer months, but this may simply indicate that it is more vocal and more conspicuous then. A single ringed adult was recovered within 1 km of the ringing site.
Breeding
The Black-crowned tchagra breeding data indicate a long summer-breeding season. The bird normally lays 2 or 3 heavily marked white eggs in a cup nest in a bush and tree. Egg-laying in the Transvaal spans Sep till Jan with a peak observed in October–December, and August–April with an October–November peak in Zimbabwe. The female incubates eggs for 12 to 15 days to hatching, and baby Tchagra fledges after 15 days.
Interspecific Relationships
It is sympatric over a large area with the Three-streaked Tchagra and over a smaller area with the Southern Tchagra. The ecological separation of the three species is unclear and this species is often encountered in close proximity to, and in the same habitat as, the other two, although the Black-crowned Tchagra tends to be restricted to the denser bush.
Distribution and Conservation
The Black-crowned Tchagra is likely to have decreased in areas where intensive agriculture and urbanization have replaced natural vegetation, but its present distribution is not believed to differ significantly from that of the past. The distribution shown in KwaZulu-Natal is very similar to that reported in Cyrus.
Food
The food habits of black-crowned Tchagra are similar to other shrikes, often hunting the insects, and small prey from a perch on the tree or in a bush. Also, the baby bird has a brown cap and a pale yellow bill, and the sexes are similar to other shrikes.
Song / Call / Sounds
So, nearly 14 subspecies were found, different in size and the color of the back, underparts, and eyestripe. This bird has a melodious descending whistling song, chee-chee cheroo cheroo, and can be immediately tempted into sight by imitating this call, apparently because the bird is concerned that there is an intruder in its territory. The male bird also has a switchback display in flight.
