The trocaz pigeon, Madeira laurel pigeon or long-toed pigeon (Columba trocaz) is a pigeon endemic to the island of Madeira, Portugal. It is a mainly grey bird with a pinkish breast; its silvery neck patch and lack of white wing markings distinguish it from its close relative and probable ancestor, the common wood pigeon. Its call is a characteristic six-note cooing, weaker and lower-pitched than that of the wood pigeon. Despite its bulky, long-tailed appearance, this pigeon has a fast, direct flight.
A scarce resident breeder in laurisilva forests, the trocaz pigeon lays one white egg in a flimsy twig nest. Its numbers fell sharply after human colonisation of the Madeira archipelago, and it vanished altogether from Porto Santo Island. The major cause of its population decline was habitat loss from forest clearance, but hunting and nest predation by introduced rats were also contributory factors. Protection of the laurel forests and a ban on hunting have enabled numbers to increase, so that the species is no longer endangered.
Description
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 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
thumb|right|Old illustration based on a specimen obtained by Mr Carruthers of Madeira in 1827
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. 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. This species is protected under the European Union Birds Directive, and the laurel forests under the Habitats Directive.