Trocaz pigeon

The trocaz pigeon is a rather plain, dark grey bird long with a wingspan. When flying, it appears heavy and large-tailed, although its flight is rapid and direct. Bolle's pigeon is more similar in appearance to the trocaz pigeon, although it lacks the whitish neck patch and has a more extensively pink breast. However, that species is endemic to the Canary Islands, so there is no range overlap. The only other pigeon currently present on Madeira is the feral pigeon; this is slimmer, has more pointed wings and a much smaller tail. It often has dark wing markings, and a lighter flight. ==Taxonomy==

The genus Columba is the largest within the pigeon family, and has the widest distribution. Its members are typically pale grey or brown, often with white head or neck markings or iridescent green or purple patches on the neck and breast. The neck feathers may be stiffened and aligned to form grooves. One of several subgroups within Columba consists of the widespread Eurasian common wood pigeon, Bolle's pigeon, the trocaz pigeon, and the African Afep pigeon. The two Macaronesian endemic pigeons, Bolle's and trocaz, are thought to be derived from isolated island populations of C. palumbus. The Atlantic archipelagos of the Canaries, Azores, and Madeira have a volcanic origin and they have never been part of a continent. The formation of Madeira started in the Miocene and the island was substantially complete by 700,000 years ago. At various times in the past, the major islands of these archipelagos were all colonised by ancestral wood pigeons, which evolved on their respective islands in isolation from the mainland populations. Mitochondrial and nuclear DNA sequences suggest that the ancestor of Bolle's pigeon may have arrived in the Canaries about 5 mya, but an older lineage that gave rise to another Canarian endemic, the laurel pigeon, C. junoniae, may date from 20 mya. The most recent wood pigeon arrival on Madeira was that which gave rise to the subspecies C. palumbus maderensis. Trocaz is a variant of Portuguese torcaz, the common wood pigeon; both words are ultimately derived from the Latin torquis, a collar, and refer to the bird's coloured neck patches. This is a monotypic species, although in the past Bolle's pigeon was sometimes regarded as a subspecies of the trocaz pigeon. ==Distribution and habitat==

The trocaz pigeon is endemic to the mountainous subtropical Atlantic main island of Madeira, although it formerly also bred on the neighbouring Porto Santo Island. It mainly occurs on the northern slopes of the mountains, but smaller numbers are found in the south where suitable patches of laurel forest remain. The natural habitat is tall laurisilva forest or dense tree heaths which are cloud-covered for much of the year. The forests consist mainly of laurel, Ocotea foetens, Madeira mahogany, Canary laurel, faya, lily-of-the-valley-tree and Picconia excelsa. The trocaz pigeon prefers primary forests, but secondary growth is used for feeding, and agricultural land is also visited, especially at times of fruit shortage. Most of the pigeons are found below , and their prime environment appears to be steep ravine-indented slopes along artificial watercourses, with the occasional large dead laurel tree and much tree heath. This species is highly mobile between different areas at different times of year. ==Behaviour==

Breeding described the trocaz pigeon as Trocaza bouvryi in 1855 Pigeons can breed from their first year, and nesting occurs throughout the year, although mainly from February to June. The displays are similar to those of the common wood pigeon; the male climbs quickly in flight, gives a loud wing-clap, and then glides down with his wings and tail spread. The display may be repeated two or three times before the bird returns to a perch. On the ground the male performs a bowing display with his neck inflated to show off the iridescent neck patches; meanwhile, the tail is raised, fanned, then closed again. This display is usually accompanied by calling. The nest is a typical pigeon construction, a flimsy structure of twigs and grasses usually placed high in a tree in thick forest. One, rarely two, smooth white eggs are laid, The eggs, in size, are incubated for 19–20 days; the young are able to fly in 28 days, and are independent within eight weeks. This pigeon will feed in agricultural areas, where cabbage is the most commonly taken crop plant. Pigeon faeces from agricultural areas contain few native plants, and samples from forests have few crop species, so some individual birds may concentrate on crops. Feeding in cultivated land is commonest in winter, when fruit is readily available, so it appears not to be a shortage of natural foods that causes them to leave the forest, but is mostly opportunistic, resulting from the birds' movements through nearby forest. However, when the fruit crop of Til and Azores Laurel is poor, large numbers of pigeons may leave the forest to feed on cabbage, flowering cherries and vine shoots. Competition for food with rats can be significant in parts of the island. ==Status==

The trocaz pigeon formerly bred on both the main island of Madeira and nearby Porto Santo Island. It was very abundant when the islands were first colonised by humans, but was extirpated on Porto Santo, and by 1986 had declined to about 2,700 birds. Hunting was banned in that year, and there are now between 7,500 and 10,000 individuals in approximately of suitable habitat. The losses on the two islands, the only inhabited ones in the archipelago, were largely the result of deforestation for wood and to create agricultural and grazing land. This species is protected under the European Union Birds Directive, and the laurel forests under the Habitats Directive. ==References==