A plague of hungry quela quela birds has devastated up to 70% of farmers' crops in northern Nigeria.
The red-billed quela birds fly in huge flocks (Pic: ARC-PPRI)
A BBC correspondent in Yobe state said farmers were in their fields beating drums to scare the birds away.
The birds fly in densely packed flocks and are one of the world's most abundant species.
The area borders Niger which is suffering from severe food shortages because of last year's drought and locust invasions.
Journalist Mustapha Mohammed, who visited Gadana in north-eastern Yobe state, told the BBC's Focus on Africa programme that thousands of the small dark birds with red beaks were hovering in the sky.
Farmers were distraught, he said, and had taken to sleeping in their fields fearing further invasions.
"We started three days fasting and prayers, hoping for Allah's intervention against these destructive birds that are threatening our means of existence," village head Sule Aliyu said in an interview on state radio.
State and local officials say more than 8,000 hectares of crops - mainly millet - has been destroyed, with tens of thousands of peasant farmers affected.
"The birds are migratory; most of them came from Niger where they could not find food to eat," agriculture official Tukur Maru said.
The area already has a low crop yield due to desertification.
Agricultural Minister Malam Adamu Bello told the BBC's Hausa service that the government planned to start aerial pesticide spraying soon.
An earlier spraying campaign in June failed to stop the invasion.