Turtles' homing performances.

acame only within 23 km of home in 60 hours; path stopped at 203 km of home (Madagascar).bcame only within 27 km of home in 14 days; path stopped at 256 km of home (Aldabra).ccame within 21 km of home in 44 days; path stopped at 112 km of home (battery exhausted).dcame only within 13 km of home in 4 days; path stopped at 227 km of home (Madagascar).The global path and central phase efficiencies were estimated as the mean cosine of directional errors. The initial phase efficiency was estimated as the number of 5-km steps travelled (with respect to water masses) before the turtle considered definitely took the correct ±90° direction. The final phase efficiency was estimated as the mean of the squared distances between successive locations and home when the turtle came within 50 km of home. CO: control group; MB: magnetic treatment on the nesting beach, prior to displacement; MH: magnetic treatment during homing.