Supplementary material from "Tidal drift removes the need for area-restricted search in foraging Atlantic puffins"

Understanding how animals forage is a central objective in ecology. Theory suggests that where food is uniformly distributed, Brownian movement ensures maximum prey encounter rate, but when prey is patchy, the optimal strategy resembles a Lévy walk where Area-restricted search (ARS) is interspersed with commuting between prey patches. Such movement appears ubiquitous in high trophic-level marine predators. Here, we report foraging and diving behaviour in a seabird with a high cost of flight, the Atlantic puffin (Fratercula arctica), and report a clear lack of Brownian or Levy flight and associated ARS. Instead, puffins foraged using tides to transport them through their feeding grounds. Energetic models suggest the cost of foraging trips using the drift strategy is 28–46% less than flying between patches. We suggest such alternative movement strategies are habitat-specific, but likely to be far more widespread than currently thought.