São Tomé Ibis

Zwergolivenibis

The Zwergolivenibis ( Bostrychia bocagei ) is a rare species of bird in the family of the ibises and spoonbills. It is endemic to São Tomé. By 1993, the taxon was considered a subspecies of the Olivenibis ( Bostrychia olivacea ).

Description

The Zwergolivenibis reached a size of 60 to 65 centimeters. The wing length is 248 mm, the beak length 73 mm, the run length 52 mm and tail length 95 mm. Head and body of the adult birds are dunkelolivbraun. Mantle and wing-coverts have a bronze green shimmer. The beak is light brown with a bright red beak first. To the eyes and the beak base is a dark area. The Zwergolivenibis is mostly silent, occasionally is a kah kah - gah - gah heard.

Habitat and behavior

The Zwergolivenbis inhabits primary forest below 450 m. Although suitable habitat is present also at altitudes up to 800 m, the species was most common at the boundary between primary and secondary forests and occasionally observed in recent years near Palm plantations. He goes on lowland forest soils in areas with little undergrowth in search of food, especially where the ground was churned up by wild boars and in wetlands that are adjacent to watercourses. Its diet consists of invertebrates, snails and slugs. Little is known about its breeding biology. Two nests were discovered in 1997. The birds forage at night on a common sleeping tree and can be identified by their reputation when they approach or leave the roost.

Status

Prior to its rediscovery in the valley of Ana Chaves in 1990, only a few copies of Zwergolivenibis have become known. In May 1997, two pairs, another individual and two nests were discovered in the basin of the rivers Rio Grande io and Martim Mendes. Additional copies were observed in 2007 in the Obo Natural Park in Ribeira Peixe. Due to the lack of proof BirdLife International estimates the stock at 50 to 250 copies.

In the past, wide range of lowland forests cocoa plantations were replaced. In the future, the increasing number of small farms and the associated clearing of trees could further restrict the habitat of the Zwergolivenibis because the road along the east and west coast to the remote areas of Sao Tomes increases more and more. A potential hazard is due to invasive mammals such as rats, Mona monkeys, African civets and weasels. However, the most serious threat is hunting dar. 1996/1997 16 ibises were killed by hunters and also during the research in 2007, hunters in the Obo Natural Park were present.