Dongying in East China's Shandong province is a city located where the Yellow River meets the Bohai Sea and is a key stopover on the East Asian–Australasian and Pacific Flyways. Every October to April, tens of thousands of birds fill the sky above the estuary in shapes that resemble a giant whale or drifting clouds.

The sunset glow above the Yellow River Delta National Nature Reserve blends yellow and blue across the sky. [Photo/VCG]

Visitors observe and appreciate the landscape of the Yellow River Delta National Nature Reserve. [Photo/VCG]

Migratory birds traverse the sky in a single line. [Photo/VCG]

Visitors admire the landscape by the white reed banks. [Photo/VCG]

A group of birds flies over the thriving wetlands. [Photo/VCG]