Post-Fledgling Survival of the Cooperatively Breeding Puff-Throated Bulbul (Alophoixus Pallidus)

Abstract

Abstract. In the tropics, passerines are expected to have survival rates higher than those in temperate zones, though their post-fledging survival has rarely been quantified. Furthermore, because of increased care by adults, cooperative breeding species should have even higher rates of juvenile survival, but few data are available on such species also. Over three breeding seasons we examined factors relating to post-fledging survival of the cooperatively breeding Puff-throated Bulbul (Alophoixus pallidus) in an evergreen forest in northeastern Thailand. These factors included the presence of helpers, fledgling age, sex, body mass prior to fledging, date of fledging within a year, and variation by year. The probability of surviving the 8-week period of dependency was 0.61 ± 0.09 (SE), higher than most reports from the temperate zone. Survival probability was strongly associated with age though not with the presence of helpers. Weekly survival was lowest during the first week post-fledging (0.73 ± 0.08), wh...