This eerie footage shows thousands of swallows circling in the sky above building tops before dozens of them froze and dropped dead on the ground amid below zero-temperatures.

Footage captured by residents shows the flock of birds flying erratically above the buildings in Laibin, in China's southern Guangxi Region, on November 13.

Shocked locals said the swallows flew around in circles before they suddenly began dropping from the sky in the freezing temperatures.

Heart-breaking footage shows dozens of them lying dead on the road after not being able to withstand the cold.

Swallows are small to medium-sized birds known for their sleek, streamlined bodies and graceful flight. Species found in colder regions migrate during the winter when their insect prey populations collapse.