Core Concepts
Birds utilize ships for migration, offering a new strategy for long-distance travel.
Abstract
Birds worldwide hitchhike on ships during migrations, with millions estimated to rest on boats. Ship-assisted migration provides crucial stopovers and food sources for birds crossing oceans, potentially aiding in colonization of new regions.
Stats
"On average, he saw three birds arrive on the boat every day."
"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."
"Even counting only the commercial shipping fleet, around 90,000 ships are regularly crisscrossing the world’s waters."
"In about half of these cases, Lees says, the committee suspects the bird has arrived with the help of a boat."
"The best evidence of ship-assisted colonization comes from a bird that doesn’t usually migrate at all: the Indian house crow."
Quotes
"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." - Alexander Lees