Yoshinori Mizutani was in for a surprise after seeing hundreds of parakeets flocked towards an elm tree near his home.

The photographer Yoshinori Mizutani's interest began when he started seeing flocks of parakeets every morning in Tokyo's Setagaya ward flying towards an elm tree near his home.

The parakeets, birds with bright-green feathers and scarlet beaks, are uncommon in Japan. The photographer's attention was caught when he began to see more and more of the birds every day. At the same time, he began to fear.

'I felt as if I'd walked into the Alfred Hitchcock film 'The Birds,' he said.

Due to his interest - and maybe his fear, too - the photographer researched about the parakeets and disovered that there was a large nest in one of Tokyo's suburbs, Ookayama. He visited the site, inhabited by hundreds of birds, and started photographing them.

He then learned that the parakeets he saw where descendants of those who were owned in years' past by Japanese. Unfortunately, it didn't make for great pets as most of them were noisy. As a results, many of the parakeets were released by their owners.

Normally, according to experts, birds such as the parakeets wouldn't last long with Tokyo's climate. However, these particular hundreds of birds have adapted to the cold. 'I had an uncanny feeling when I first saw them. I decided to work on "Tokyo Parrots," a project that captures a surreal and extraordinary urban landscape,' Mizutani said.

Mizutani now takes photos of the parakeets with the aid e of a strobe light. According to him, the birds would appear as a dark shadow in the sky when photographed from below and without the light.

As he continued to take photos of the birds, the photographer also began to learn more about them and their behavior. '(The) parakeets live in ginkgo trees, and I wanted to capture them with the changing background of the four seasons, especially with the ginkgo leaves turning yellow in autumn. I learned that they change the tree on which they build nests and the time and direction they take to return home depending on the season,' he said.

For Yoshinori Mizutani's photos, check out his Facebook, Twitter, Tumblr and Instagram accounts.