Offshore wind farms are turning into seal hunting grounds. The wind farms Alpha Ventus, 56 kilometers from Germany’s shores, and Sheringham Shoal (pictured), 23 kilometers from the United Kingdom’s shores, have become home for fish and crustaceans homing in on invertebrates like mussels clustered on the massive structures. These animals, in turn, attract harbor and gray seals (Phoca vitulina and Halichoerus grypus), researchers report this week in Current Biology. To make the discovery, the scientists attached GPS tags to seals of both species off the North Sea’s British and Dutch coasts—a popular spot for wind farms. They recorded seals visiting wind farms repeatedly, tracing out an unusual gridlike pattern as they swam from turbine to turbine (as in this video). This coordinated behavior suggested that the seals had found plentiful prey at each turbine. It’s still unclear whether these structures increase prey numbers or just concentrate them in one area; if it’s the latter, prey populations could suffer if more seals target these feeding grounds.