Colombo imperiale di Torres

Identificazione

The Torresian imperial pigeon is a large plump pigeon, 38-44 centimetres (15-17.5 inches) in length, and with a 45 cm (18 in) wingspan. It is entirely white or pale cream, apart from the black flight feathers (remiges), part of the tail (rectrices) and spots on the undertail coverts. The head can be brown, soiled by eating fruit.

Tassonomia

Its taxonomy is confusing and remains unsettled. It has sometimes been considered a subspecies of the pied imperial pigeon. When recognized as a separate species, the number of subspecies of the Torresian imperial pigeon also remains unsettled. Many recognize two: The widespread D. s. spilorrhoa (nominate) and D. s. constans of the Kimberleys. However, the latter is sometimes considered a junior synonym of former. Alternatively, it has been argued that it should be considered a separate species, the Kimberley imperial-pigeon (D. constans Bruce, 1989).<p>Two additional taxa, subflavescens of the Bismarck Archipelago and melanura of the Moluccas, have been associated with the Torresian imperial pigeon. The former has a distinctive yellowish-tinged plumage and a bluish basal half of the bill, and is increasingly treated as a separate species, the yellowish imperial pigeon (D. subflavescens). Most recent authorities place melanura under the pied imperial pigeon, but it has black spotting to the undertail coverts and a greenish-yellow bill similar to the Torresian imperial pigeon. However, melanura also has a significantly broader black tail-tip than the Torresian imperial pigeon.

Nome scientifico

Ducula spilorrhoa

Autorità

(Gray, GR, 1858)

Ordine

Columbiformi

Famiglia

Columbidae

Genere

Ducula

Areale e habitat

Migrazione

Complete migrants

Comportamento

The flight of the pigeon is fast and direct, with the regular beats and an occasional sharp flick of the wings which are characteristic of pigeons in general.<p>The male displays by flying up steeply, pausing, tipping forward and then gliding downwards. The female builds an untidy stick nest in a tree, usually a coconut palm and lays a single white egg, which hatches within 26 to 28 days. The squab fledges after another three weeks. In Australia they breed between August and January in mangroves, vines, palm fronds on off-shore islands, such as the Brook Islands. In north-east Queensland, they migrate daily as flocks from the islands to the mainland rainforests to eat fruit, returning to the islands at dusk.<p>This is an arboreal dove, feeding almost exclusively on fruit. It can swallow fruits with very large seeds, the latter being regurgitated or excreted whole, depending on size, after the pulp has been removed.<p>Calls made by the birds are a deep "mrrrooooo", "roo-ca-hoo" and "up-ooooo".

Conservazione

Tendenza della popolazione

declining