Dwarf olive ibis

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Dwarf olive ibis
Dwarf olive ibis

Dwarf olive ibis

Systematics
Class : Birds (aves)
Order : Pelecaniformes
Family : Ibises and spoonbills (Threskiornithidae)
Genre : Bostrychia
Type : Dwarf olive ibis
Scientific name
Bostrychia bocagei
( Chapin , 1923)

The dwarf olive ibis ( Bostrychia bocagei ) is a rare species of bird from the ibis and spoonbill family . It is endemic to São Tomé . Until 1993 the taxon was considered a subspecies of the olive ibi ( Bostrychia olivacea ).

description

The dwarf olive ibis reaches a size of 60 to 65 centimeters. The wing length is 248 mm, the beak length 73 mm, the barrel length 52 mm and the tail length 95 mm. The head and body of the adult birds are dark olive brown. The mantle and wing covers have a bronze-green sheen. The beak is light brown with a light red beak ridge. There is a dark area around the eyes and at the base of the beak. The dwarf olive ibis is mostly silent, occasionally a kàh-gàh kàh-gàh can be heard.

Habitat and way of life

The dwarf olive bis inhabits primary forests below 450 m. Although suitable habitat is also available at altitudes up to 800 m, the species has been observed most frequently in recent years at the border between primary and secondary forests and occasionally in the vicinity of palm plantations. It searches for food on lowland forest floors in areas with little undergrowth, especially where the ground has been churned up by wild boar and in swamp areas that border watercourses. Its diet consists of invertebrates, snails and slugs. Little is known about its breeding biology. Two nests were discovered in 1997. The birds look for a common sleeping tree at night and can be identified by their call when they fly to or from the roost.

status

Before its rediscovery in the Ana Chaves river valley in 1990, only a few specimens of the dwarf olive ibis were known. In May 1997, two pairs, another individual and two nests were discovered in the basin of the Rios Ió Grande and Martim Mendes rivers. Further specimens were observed in 2007 in Obó Natural Park near Ribeira Peixe. Due to the limited evidence, BirdLife International estimates the stock to be 50 to 250 specimens.

In the past, large areas of the lowland forests had to give way to cocoa plantations. In the future, the increasing number of small farms and the associated clearing of trees could further restrict the habitat of the dwarf olive ibis, as road construction along the east and west coast to the remote areas of Sao Tome is increasing. Invasive mammals such as rats, monkey cats, African civets and weasels pose a potential threat. The most serious threat, however, is the hunt. In 1996/1997 16 ibises were shot by hunters and also during the research in 2007 hunters were present in Obó Natural Park.

literature

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