This article was originally featured on Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com. Between March and May each year, 15 million black-legged kittiwakes gather from across the North Atlantic and Pacific Oceans to nest and breed on rocky Arctic cliffs—some making the journey from as far as Florida or North Africa. But a new study suggests these seabirds don’t arrive empty-handed. They carry souvenirs fr...