Ecology and social organization of a tropical deer (Cervus eldi thamin)

From 1995 to 1999. we conducted an ecological study of thamin (Cervus eldi thamin) at Chatthin Wildlife Sanctuary in central Myanmar; we maintained re cords on deer sightings and radiotracked 11 adult male and 8 adult female d eer. Based on 747 sightings, a 0.63: 1.0 adult male : female ratio and 0.51 : 1.0 fawn : adult female ratio were observed. Mean group size was variable (1.0-5.9 deer) and showed seasonal differences, with few groups observed i n August-September and groups of less than or equal to 70 individuals obser ved in March-April. Based on the fixed-kernel method, annual home range was 9.04 km(2) +/- 5.67 SD and 7.25 km(2) +/- 3.45 SD for males and females. r espectively. Thamin increased their seasonal home range during the hot-dry season, possibly in response to decreased forage and water availability and increased mating activity. The observed synchrony of estrous onset (March- April) and fawning (October-November) in female thamin is unusual for a tro pical cervid species, but reproductive seasonality appears timed to balance fawn survival with doe nutrition in a monsoon environment.