Strong winds reduce foraging success in albatrosses.

Abstract

Knowledge of how animals respond to weather and changes in their physical environment is increasingly important, given the higher frequency of extreme weather recorded in recent years and its forecasted increase globally.^1,2 Even species considered to be highly adapted to extremes of weather, as albatrosses are to strong winds,^3,4,5 may be disadvantaged by shifts in those extremes. Tracked albatrosses were shown recently to avoid storms and the strongest associated winds.⁶ The drivers of this response are so far unknown, though we hypothesize that turbulent storm conditions restrict foraging success, possibly by reducing the detectability or accessibility of food, and albatrosses divert toward more profitable conditions where possible. We tested the impact of the physical environment-wind speed, rainfall, water clarity, and time of day-on feeding activity and success of two species of albatrosses with contrasting foraging strategies. We tracked 33 wandering and 48 black-browed albatrosses from Bird Island (South Georgia) with GPS and immersion loggers, and 19 and 7 individuals, respectively, with stomach-temperature loggers to record ingestions, providing an in-depth picture of foraging behavior. Reduced foraging profitability (probability of prey capture and overall mass) was associated with stormy conditions, specifically strong winds and heavy rain in surface-seizing wandering albatrosses, and the probability of prey capture was reduced in strong winds in black-browed albatrosses. We show that even highly wind-adapted species may frequently encounter conditions that make foraging difficult, giving context to storm avoidance in albatrosses.