The latest birds update of the IUCN Red List of Threatened Species will be released on May 14 by BirdLife International, the official IUCN Red List Authority for birds.
The latest results will show that a number of species have deteriorated, including the Sidamo Lark (Heteromirafra sidamoensis), which has moved from Endangered to Critically Endangered on the IUCN Red List.
Found only in south-central Ethiopia, its global range was previously estimated at 760 km2 with a population size of almost 2,000 individuals. But studies in 2007-2008 by researchers from BirdLife, the University of Cambridge, Ethiopian Wildlife and Natural History Society (BirdLife in Ethiopia) and University of East Anglia show that available habitat covers just 35 km2. Density estimates show a global population estimate of just 90-256 adults, all found on the Liben plain.
This information was recently published as a paper in the journal Animal Conservation. If the Sidamo Lark were to go to extinct, it would have the dubious honour of being the first known bird extinction for mainland Africa.
The lark is adapted to Ethiopia's rangeland – the savanna of native grasses that traditionally covered large parts of East Africa but is now rapidly disappearing. In areas where the Liben plain has been overgrown by bush, converted into farmland or destroyed by overgrazing, the team rarely found Sidamo Larks.
“If the situation doesn’t improve soon, this species could disappear in as little as four years,” says Kiragu Mwangi, one of BirdLife’s team members.
The Sidamo Lark seems to be dependent on grassland 5 to 15 centimetres tall. Away from the Liben plain, there is no similar vegetation for over 200 km, meaning the lark has nowhere else to go.
“It's effectively like living on an island, and that's where most extinctions happen,” says Dr Claire Spottiswoode, from the University of Cambridge and lead author of the paper.