TEMPORAL AND SPATIAL VARIATION IN DISPERSAL IN THE GREATER FLAMINGO (PHOENICOPTERUS-RUBER ROSEUS)

We studied movements of individually marked greater flamingos (Phoenic opterus ruber roseus) born in the Camargue, southern France, between t heir two most important breeding colonies in the western Mediterranean (Camargue and Fuente de Piedra, Spain) from 1986 to 1992. The two sit es differ in the frequency with which they offer suitable conditions f or breeding. Flamingos have bred each year in the Camargue since 1974, but in only 12 of the past 22 years at Fuente de Piedra. Higher colon y fidelity is thus expected ill the less variable environment (Camargu e), but if dispersal occurs competition might be an important factor c ausing this dispersal. Following years during which breeding birds in the Camargue were disturbed (1988 and 1990) a higher proportion of adu lts changed colonies between breeding attempts (= breeding dispersal, 12.4%), while only 0.4% of flamingos breeding in the Camargue disperse d in the other years. As expected, flamingos breeding at Fuente de Pie dra showed a higher rate of breeding dispersal (8.14%). No differences were observed between males and females. The importance of breeding f ailure as a factor causing breeding dispersal in flamingos was also co nfirmed by the movements of individual birds. The proportion young fla mingos that moved from their natal colony to start breeding at Fuente de Piedra (= natal dispersal) was independent of sex and age, but incr eased when breeding access to the Camargue colony was more difficult. However, natal dispersal was also higher in 1988 and 1990 (40.5%) than in the remaining years (1.2%), as was breeding dispersal. We discuss possible ways in which the increased natal dispersal among inexperienc ed birds could be linked with the increased breeding dispersal of adul ts in the same year.