Sky Burial(1971)

Chousou

Nogawa suspects that he is being followed by vultures. Scared, he secludes himself, dropping out of college and breaking up with his girlfriend. When it is discovered that his neighbor had been dead for three months, his friend and other neighbors move out. However, with nowhere to go, Nogawa stays as the building succumbs to nature and a group of vultures roost on the roof.

(Source: Wikipedia)