Birds are now using boats to cross oceans, even when they shouldn't. Fucking awesome. Birds are so cool.

Birds are often unexpected stowaways on ships around the world. Freighter crews have long told stories of sparrows and nightjars, owls, and herons settling on their boats’ decks, some for minutes, others for days. There’s video footage of a whole flock of starlings landing on a fishing boat in the North Sea. And after conservationists tagged a young osprey in Scotland, they watched with bemusement as the bird’s tracking signal showed its voyage to Spain involved riding on a cargo ship. The bird switched to a second vessel mid-journey before finishing the trip on its own.

In 2021, Sarà, a zoologist at the University of Palermo in Italy, planned to observe dolphins, turtles, and other marine species. But he kept noticing terrestrial birds, like wagtails and wheatears, landing on the boat. He started keeping track. On average, he saw three birds arrive on the boat every day. Their median stopping time was 42 minutes but several stayed overnight. Extrapolating from his observations to the thousands of ships that travel the Mediterranean every day and the billions of birds that cross the sea during their migrations, Sarà estimates that as many as four million birds may be taking rest stops on boats during their spring migrations across the Mediterranean.

It’s surprising how well birds can survive even entire ocean crossings on deck, Lees says. “Grain eaters tend to get handouts from people, such as crisps. And insectivores may find windblown insects. Raptors use the boat as a perch to hunt seabirds,” he says.

Every so often, this could allow a species to colonize a new region. The best evidence of ship-assisted colonization comes from a bird that doesn’t usually migrate at all: the Indian house crow. In recent years, so many of these birds stowed away on boats to the Netherlands from their native South Asia that they’ve established a breeding colony near Rotterdam.