This giant flock of birds that swarmed over city streets and covered cars and utility poles in droppings sparked worry if it might be a sign of future calamity.

Phone footage shows thousands of swallows flying low above the street near the Longjing Market, in Shantou, in Guangdong Province, China, on the night of December 26.

Many residents said they saw birds stopping on car roofs, doors, windows, and electric poles, and they were unsure why they came.

They flew in dense groups and left bird droppings all over parked cars, causing panic and frustration among locals.

One resident said that although the area usually has many birds gathering, that night was particularly busy, and she was unsure about the cause.

Huang Zhen, a member of the China Wildlife Conservation Association and the Chaoyang Photography Association, explained that swallows are found all over Shantou throughout the year.

He said the unusual behaviour may be due to foraging or weather conditions, according to Huang, rather than it being a sign of a natural disaster.

Researcher Chen Huizhong from the Institute of Earthquake Forecasting also stated that although animals can behave abnormally before some earthquakes, it is not always apparent.

Various factors, such as climate, weather, and environment, can also cause abnormal reactions in animals, that do not necessarily indicate an earthquake precursor.

The swallow is a small to medium-sized bird characterised by its distinctive pointed wings, forked tail, and agile, acrobatic flight.

Swallows are known for their sleek, streamlined bodies and are often adorned with vibrant plumage.

They are found worldwide and are recognised for their migratory behaviour, covering long distances during seasonal journeys.