SREL Reprint #1931|
FORAGING STRATEGIES AND ENERGETIC COSTS
OF FORAGING FLIGHTS BY BREEDING WOOD
COLIN J. PENNYCUICK
Abstract. Wood Storks (Mycteria americana) were followed (n = 269) from
their colony in east-central Georgia to foraging sites to examine the foraging travel
strategies of these birds. Most sites were relatively close to the colony (median
distance = 8.8 km) requiring short travel times (median time = 22.52 min).
Directness ratios (total distance flown/direct distance) for 89 mapped foraging
flights suggested that storks flew relatively straight paths to feeding areas.
Comparison of flight (air) speeds determined from this data with speeds
determined from energetics models suggested that storks minimized flight energy
costs rather that maximized range during foraging travel. Estimated energetic
costs of flapping and soaring modes of flight were 204.8 W and 18.1 W,
SREL Reprint #1931
Bryan, A.L., Jr., M.C. Coulter, and C.J. Pennycuick. 1995. Foraging strategies and energetic costs of foraging flights by breeding wood storks. The Condor 97:133-140.