As peckish deer chase delighted tourists in Japan's temple-dotted Nara Park, a quiet but dedicated team of litter-pickers patrols the stone paths, collecting plastic waste that threatens the animals' health.

The ancient city of Nara is a major draw for the country's record influx of visitors — but like in nearby Kyoto, where photo-hungry crowds have been accused of pestering the famous geisha, there have been unwelcome consequences.

Tourists are only allowed to feed the deer special rice crackers sold in Nara, but the animals are increasingly eating rubbish by accident.