Farmland green treefrog (Rhacophorus arvalis) belonging to the family Rhacophoridae is endemic to Taiwan. The mating system of Rhacophorus arvalis is lek. From April 2003 to June 2004 at Yunling in central Taiwan, I investigated the lekking behavior and daily activity pattern, and analyzed the ecological factors on habitat to understand the lek preference in male frogs. During breeding seasons, the results showed that there were present consistent lekking sites on habitats. There were 0~38 males in the lek every night, and the number of males were affected by the amount of rainfall.
