"That family will prosper. They will have more children, more cattle," said Jarso Denge, a Borena National Park tour guide, in explaining his parents’ enthusiasm for such nests when he was growing up over a phone interview.
The increasingly rare birds could use more good luck themselves.
The white-tailed swallow and the Stresemann’s bush-crow are two native Ethiopian bird species threatened not only by climate change – manifested in part by the deadly drought in East Africa – but also by encroaching human development.
The Borana Zone covers roughly 45,400 square kilometers in southern Oromia region, bordering Kenya to the south. The zone, predominantly rangeland, is the only known habitat for the two bird species – and their populations are declining.
Andrew Bladon, a conservation ecologist with the University of Cambridge’s zoology department and his research team – which has included Denge– have studied the two species extensively.
Drought is devastating the birds, Bladon said. Without adequate water, they get dehydrated and can’t regulate their body temperatures.
Bladon made several trips from Great Britain to Ethiopia, spending a total of six months with his team observing how temperature affects the swallows’ and bush-crows’ behavior, breeding and preservation.
"Unlike humans, birds cannot sweat but instead use panting to increase airflow over their throats, which helps them cool down," Bladon said.
But in drought-stricken Borana, there’s now less water for birds to consume and cool themselves.
Bladon and his team found 35 nests of bush-crows, which tend to live close to semi-nomadic people and their cattle and goat herds. The researchers documented hatchings and how the chicks grew, measuring feathers, taking photographs and recording the birds’ habits.
The bush-crow, also called Qaqa because of its call, "helps cows by eating fleas off them, and in turn there are worms that live in cows’ dung and Qaqa consumes those. The benefit is mutual," Denge said.
These birds forage among livestock herds, as they have with wild grazers such as elephants, zebras and wildebeest. Though the elephants have disappeared, the other wild and domesticated animals keep the landscape open and create ideal habitat for the birds, according to Bladon. He said the white-tailed swallow also prefers areas with low to mid-level densities of cattle and goats.
In the 1990s, Ethiopia’s central government began pushing to diversify the economy, encouraging more farming and herding at the same time. Agriculture requires that farmers and their animals stay in one place – a challenge in the semi-arid Borana Zone.
Overgrazing and increased land cultivation are helping to drive down the white-tailed swallow and bush-crow flocks, Bladon and others say.