RESEARCHERS FIND SEABIRDS DEFECATE ONLY WHILE FLYING
Seabirds are not only important predators in the open ocean, they also move nutrients through their droppings. A new study of streaked shearwaters (Calonectris leucomelas) in Japan has revealed that these birds almost never defecate while resting on the sea surface. Instead, they excrete during flight, and at a regular pace of every four to ten minutes. Using small cameras attached to the birds, researchers found that a single shearwater can release about five percent of its body weight in droppings per hour.
This behaviour could have wider consequences for the marine environment. Much like whales, which are known to recycle nutrients through the so-called “whale pump,” seabirds may fertilise the ocean as they travel. With hundreds of millions of shearwaters and related species across the globe, their excretion could influence plankton growth and, in turn, the food webs that support fish and other marine life. The study highlights how even a basic behaviour, such as where and when birds relieve themselves, can shape the functioning of entire ecosystems.
Reference: Uesaka & Sato. 2025. Periodic excretion patterns of seabirds in flight. Current Biology
Streaked shearwater dropping recorded with a belly-mounted video camera by Uesaka & Sato.
Streaked shearwater photograph by Hong.
