The sky was blanketed with countless black birds, circling overhead and filling the air with their eerie calls in northern China.

The video was filmed in Tianjin on October 30.

Eyewitness Mr Xu said that he heard the incessant chattering outside. When he opened the curtains, he was met with this harrowing sight. Xu thought the birds were crows, they seemed to cover the entirety of the sky, leading to some residents fearing as if the end of days had arrived.

Wen Cheng, a bird specialist from Peking University's School of Life Sciences, explained: "A large flocks of birds such as swallows, white wagtails, sparrows, and crows gather in cities to roost for the night. They are drawn to urban areas primarily because cities tend to be warmer and have fewer predators that prey on these birds. As we transition into autumn, such occurrences can be expected."


The video was provided by local media with permission.

10月30日傍晚，天津，一小区上空出现大量黑色飞鸟盘旋鸣叫，密密麻麻布满天空。目击者徐先生称，当时听见外面叽叽喳喳，打开窗帘就看到这一幕。看着像是乌鸦，不知道为什么会突然聚集这么多，有一种末世来临的恐怖感。
对此，北京大学生命科学院鸟类专家闻丞表示，大群在城里过夜的鸟有燕子、白鹡鸰、麻雀、乌鸦等，它们在城里集中过夜的原因主要是城里更暖和或者城里以它们为食的捕猎者更少，立秋后是会有这样的情况。