Comoro Blue-Pigeon
Alectroenas sganzini
Medium-sized chunky pigeon that is dark blue with a pale gray hood. Appears short-tailed in flight. Found in rainforest, secondary habitat, and plantations, and locally in dry coastal scrub. Most common at higher elevations in most of its range. Most often seen perched up conspicuously on emergent trees, feeding on fruiting trees, or in flight in small flocks. The common vocalization is a quick series of low hoots or growls. Dark blue coloration and pale head separate it from all other pigeons in its range.
Identification
The Comoro blue pigeon measures about 27 centimetres (11 in) in length. The male weighs from 134 to 158 g (4.7 to 5.6 oz), and the female weighs about 117 grams (4.1 oz). It has a silvery gray head, neck, and upper breast. The neck feathers are silvery white in colour, and are very long and deeply partitioned. The beak is greenish or yellowish grey, and has a pale yellow or greenish white tip. It has black lower underparts. The lower part of the breast is shiny violet-blue, and the belly and flanks are more greenish blue in colour.
Taxonomy
- Scientific name
- Alectroenas sganzini
- Authority
- (Bonaparte, 1854)
- Order
- Columbiformes
- Family
- Columbidae
- Genus
- Alectroenas
Range and habitat
The Comoro blue pigeon is endemic to the Comoros and the coralline Seychelles. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical mangrove forests, and subtropical or tropical moist montane forests. It is found at elevations ranging from 500 to 1,500 m (1,600 to 4,900 ft) above sea level.
- Migration
- Resident species
Behavior
The Comoro blue pigeon is sometimes solitary, but may occur in groups of up to 15 individuals. These often fly about 10 m (30 ft) above the water between islands in the Aldabra group, making regular journeys in one direction in the mornings and back again in the evenings. Their flight is fast, interspersed with wing claps. They have a habit of perching high in a tree in full sun and raising one wing to expose it to the sun. They are arboreal, fruit-eating birds which seem to avoid landing on the ground; however, small stones found in their crop seem to indicate that they do sometimes descend to the earth.
Conservation
As of 2017, the Comoro blue pigeon has been rated as a species of near threatened on the IUCN Red List of Endangered Species. This is because although it has a restricted distribution, its range size is considered to be more than 20,000 km2 (7,700 mi2). Despite a decreasing or fluctuating range, the area of occurrence is above the criterion to warrant it a vulnerable rating. Although its population has not been determined, it is thought to be above 10,000. Also, even though its population is decreasing, the rate of decline is thought to be less than 30% over ten years or three generations and thus is below the vulnerable criteria. It is reportedly extinct in some areas, commonly found in others, and extinct on many small islands.
- Population trend
- declining
Photos
Distribution
Other Birds
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Rynchops albicollis
Unmistakable; black above and white below with bright orange bill (lower mandible longer than the upper). Favors slow-moving rivers with sandbars, on which this species forms noisy colonies, often in association with terns. Flies rapidly on long angular wings, “skimming” the water with the extended lower mandible. Gives a sharp “kip kip.”
Soft-plumaged Petrel
Pterodroma mollis
Attractive petrel with a black mask, largely gray above and white below, with a diagnostic dark breast band. Note the heavy dark bill. In flight, exhibits gray underwings and gray and dark brown M-pattern on the back. The rare dark morph has dark underparts, but still retains the distinctive complete breast band, which is the most useful mark separating this species from Fea’s and Zino’s Petrels. Usually encountered well offshore, in towering roller-coaster flights; sometimes follows boats.
Papuan Thornbill
Acanthiza murina
A small bird of upper montane and subalpine forest canopy and bushes. Dull brown upperparts, whitish underparts and yellowish tinged head, neck and upper chest. Note the white, beady eye, grizzled cheek and relatively short bill. Forages very actively and constantly, often in mixed flocks with Large and Papuan Scrubwrens. Similar to Brown-breasted Gerygone, but Papuan Thornbill is more common higher up and avoids more open habitats. Voice, various high-pitch chips and squeaks.
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