The Comparison of Reproductive Phenology and Breeding Success Between First and Second Breeder Group of Whiskered Tern (Chlidonias hybridus) in Marzoonabad Permanent Ab-bandan of Mazandaran Province

This study is carried out during May-September, 2003. Whiskered Tern (Chlidonias hybridus) observed in two breeder groups in Marzoonabad Ab-bandan. Reproductive phenology of whiskered Tern (C. hybridus) is started with nest building behavior in the first breeder group and was continued to chicks fledged time in beginnings July (1155 pairs), whereas, this behavior in the second breeder group has been started at the end of May and was continued to beginning of August (235 pairs). Clutch size was 1-4 and 1-5 eggs in the first and second breeder group, respectively. Brood size has been included 1-3 and 1-2 chicks, respectively. Breeding success in the first and second breeder group was %82.96 and %75.87. Breeding success has not any significant difference between clutch size and brood size (p> 0.05). There is significant difference (p< 0.05) between the rates of losses among the reproductive phenology stages and the maximum losses were occurred during the incubation time. Breeding success have not any significant difference in both groups (p=0.206).