Streaked shearwaters defecate almost exclusively in flight off Japan

A new study of streaked shearwaters off Japan shows these open-ocean seabirds defecate almost exclusively in flight, with a steady rhythm of roughly every four to ten minutes. Over nearly 36 hours of video footage from 15 birds, researchers recorded 195 defecation events, and only a single instance occurred while a bird was floating. The findings suggest a deliberate pattern tied to flight, with potential implications for marine nutrient cycles as well as predator avoidance and feather cleanliness.

The project began as an investigation into how seabirds manage takeoffs from the sea surface. While observing playback footage, the researchers noted the frequent excretion and pivoted to study its frequency and timing. Lead author Leo Uesaka, an atmospheric and ocean researcher, described the surprise at how often the birds pooped, saying, “I was surprised to see how frequently the birds defecated in the video footage. I thought it was funny at first, but it turned out to be more interesting and important for marine ecology.” The team attached small backward-facing cameras to the birds’ bellies to capture nearly 200 defecation events and then analyzed the timing relative to flight,...