More than five million invasive quelea birds have been killed in a mass cull in Tanzania, the authorities have said in comments reported in the local media.

The birds had invaded more than 1,000 acres of rice farmland in the Manyara region in the north of the country, causing extensive losses.

Officials spent more than four days using drones to spray the the swarms of birds with avicides, the Tanzania Times reports.

The invasive birds were capable of destroying more than 50 tonnes of food crops every day, according to Gadman Mbuko from the Tanzania Plant Health and Pesticides Authority.

Quelea birds, thought to be the most numerous bird species in the world, often destroy grains such as rice and wheat.

In 2021, the UN's Food and Agricultural Organization (FAO) estimated that $50m (£41m) worth of crops are lost to the birds each year, mostly in sub-Saharan Africa.