Breeding Biology of Pheasant-tailed Jacana Hydrophasianus chirurgus in Taiwan

The population size of Pheasant-tailed Jacana in Taiwan have greatly declined due to habitat destruction . The population decline has attracted attention and various protective actions have been taken. However, few studies have done on the Pheasant-tailed Jacana. Understanding the breeding biology of Pheasant-tailed Jacana is critical in making conservation actions or management strategies. This study was conducted from year 2002 to 2007. I recorded the population dynamics and breeding activities of Pheasant-tailed Jacana in Tainan County, the main breeding and wintering area in Taiwan. I also measured and tested the relationships between environmental variables and the breeding success rate. During the study periods, I observed 395 nests, 1466 eggs and 744 chicks. The distribution of nests was in clumps in some breeding areas. The 20 days survival rate of fledgling was positively correlated with the nearest distance to river of the nest. Because the water chestnut fields adjacent to rivers were usually flooded by the heavy rains in typhoon season and subsequently the nests and chicks had a higher chance of nest failure. It is necessary to protect the main breeding areas that most nests located and to prevent the damages of floods. his study is the first to report infanticide by male Pheasant-tailed Jacanas and to discuss its mechanisms and reproductive fitness. I suggest that male Pheasant-tailed Jacana may use infanticide as a strategy to avoid cuckoldry when the paternity of eggs is in doubt. Males can prevent investing extra-paired offsprings by infanticide. How infanticide influences the reproductive success rate of Pheasant-tailed Jacana was not clear and needed more studies.his study also discussed the evolution of the mating system and the results were consistent with the predictions of the replacement clutches hypothesis in Pheasant-tailed Jacana. The time spent on breeding behaviors (mostly incubating behavior) of male jacanas peaked around noon in late breeding stage. I suggest this was due to the high air temperature of the study site during breeding season. Males had to stay in the nests to provide eggs and chicks protection from high temperature and ultraviolet ray.