The Sidamo lark could soon be the first bird on mainland Africa to die out since modern records began.
A survey has found that just a few hundred of the larks survive in Ethiopia. Unless action is taken to save it, the bird will disappear.
While it may be the first recorded bird extinction on the continent, it will not be the last, warn conservationists.The birds inhabit a very small pocket of grassland within the Liben Plain of southern Ethiopia.
"This imminent extinction reflects a wider social and political crisis that is repeated throughout Africa," said zoologist Claire Spottiswoode of the University of Cambridge.
She led a survey of the bird's habitat and published her findings in the journal Animal Conservation.
Ancestral link
The Sidamo lark ( Heteromirafra sidamoensis ) is an enigmatic species, and one of the most ancient types of lark known anywhere.
Discovered by scientists in 1968, the bird was only seen once in the following 25 years.
"If we lose this species then we lose an important ancestral link in the evolution of the entire radiation of lark species," said Dr Spottiswoode.
This area of highland savannah used to be maintained by fire and by the grazing of large herbivores, such as elephants, antelopes and gazelles.
Borana pastoralists also traditionally walked their cattle across the plain as they migrated between different wet and dry season grasslands.
For millennia, both the wild animals and pastoralists kept the grasslands in good condition.
This habitat is now being destroyed.
Wild animals are too few to stop shrubs regrowing, while intensively reared livestock and agriculture are increasingly damaging the grasslands.
Unique habitat
Dr Spottiswoode surveyed the Liben Plain with colleagues from the Ethiopian Wildlife and Natural History Society, Birdlife International and the University of East Anglia.
They found that the Sidamo lark lives within a single patch of grassland of just 35 square kilometres.
That compares to a range of 760 square kilometres estimated by Birdlife International just last year, though that was a rough guess based on the best information available at the time.
"The Liben Plain has recently much diminished in size owing to bush encroachment and crop planting. Much of the remaining grassland is too degraded for the species to exist in it," said Dr Spottiswoode.
Worse, the survey revealed that a maximum of 358 Sidamo Larks remain.
More likely, between 90 and 250 of the birds survive. "Even the lower value might be optimistic," wrote the authors of the study.
They have recommended to the International Union for the Conservation of Nature (IUCN) that it upgrades to the bird's status to "critically endangered".
Action needed
"The roots of the problem are incredibly difficult to address," says Dr Spottiswoode.
For example, the conflict in neighbouring Somalia means that armed nomads often cross the border and move into the region to graze their cattle.
Increasing droughts and climate change also threaten the bird's habitat.
"But there are urgent short-term measures which might make all the difference to the bird surviving the next few years," said Dr Spottiswoode.
One step would be to create small plots in which cattle could graze. That would stop damage to the grassland and maintain the grass cover required by breeding females.
Shrubs should also be removed, while a limit should be placed on crops expanding further into the bird's range.
Saving the bird in the long term will require the return of the nomadic Borana pastoralists, said Dr Spottiswoode.
They could better manage the grasslands that make up the bird's unique habitat.
"Mitigation measures would benefit both. Perhaps a rare instance of human and conservation interests coinciding," she added.
Under threat
Southern Ethiopia has a suite of bird species that occur nowhere else in the world, many of them threatened.
The IUCN lists the white-tailed swallow as "vulnerable", while another endangered endemic species is the Ethiopian bush-crow, which occurs in a small area of savannah about 100 kilometres to the west of the Sidamo lark's territory.
It lives in complex and fascinating social groups, and its closest relatives live far away in the deserts of central Asia.
Like the Sidamo lark, the bush-crow has been severely impacted by bush encroachment and a shift from pastoralism to crop-planting, and has recently been given "endangered" status by the IUCN.