Résumé
We examined seasonal movements of radio-marked Black Grouse (Tetrao tetrix) in thesouthern French Alps during 1990-1996. Many hens migrated between summer and winter ranges, whereas males exhibited strong attachment to a single area. Average distance traveled from the winter range to the summer range differed significantly according to sex (males: 1.5 km, females: 2.95 km), and age (yearlings: 4 km, adults: 1.36 km). Birds of all ages displayed strong site fidelity to winter and summer areas. We found no statistical difference between median date of fall dispersal of juveniles (26October) and median date of migration of birds older than 12 months from summer to winter areas (19 October). Similarly, spring dispersal of yearlings and spring migration of adults from their winter area occurred at the same time (14 April vs. 18 April). Furthermore, dates of movements, including dispersal, were highly repeatable for a given individual. Thus, timing of movements along with data on site fidelity support the view that dispersal and migration are tightly linked in Black Grouse. This is the first study in any Eurasian grouse species demonstrating that migratory movements of adults retrace the spring dispersal route taken when they were 9-11 months old.