Movement of foraging tundra swans explained by spatial pattern in cryptic food densities

We tested whether Tundra Swans use information on the spatial distribution of cryptic food items (belowground Sago pondweed tubers) to shape their movement paths. In a continuous environment, swans create their own food patches by digging craters, which they exploit in several feeding bouts. Series of short (1 m). Tuber biomass densities showed a positive spatial auto-correlation at a short distance (25 g/m2) and to a more distant patch (at 7¿8 m) if the food density in the current patch had been low (3 m) from a low-density patch and a short distance (