Colonization patterns of Reunion Island by the Red-wiskered Bulbul (Pycnonotus jocosus)

The Red-whiskered Bulbul Pycnonotus jocosus has been introduced to Reunion island in the early seventies. Relief complexity and differences in pluviom etry between East and West sides of the mountain, make Reunion island a mod el for studying colonization process. Our results show differences in colon ization speed according to the slope. Warm and rainy surroundings of the Ea st slope are the first colonized and the ones where the density of populati on is greater than on the other slope, even today. Thus, a negative correla tion between bird numbers and elevation has been shown. In Reunion Island a nd unlike any other species introduced in Reunion, Red-whiskered Bulbul ent ers forests and does not confine itself to anthropic areas as in the other countries which he has colonized.