Date of this Version
The Auk 126(2):341-350, 2009.
We used radiotelemetry, habitat sampling, camera trapping, and line-transect surveys to explore movement patterns, distribution, and abundance of Great Argus Pheasants (Argusianus argus) in Sumatra, Indonesia. We radiotracked six adult and one subadult males. Territories averaged 14.5 ± 8.5 ha, and home-range size did not vary by month or by relative abundance of selected plant foods. Daily travel distance (849 ± 211 m) varied significantly between months but did not reflect changes in plant foods. Territories were used almost exclusively by resident males. Males preferentially used undisturbed forest (habitat I). Vegetation structure at male display sites and random points indicated that display sites were located in undisturbed forest, with few lianas and small leaf size on trees adjacent to the display site. Between 1998 and 2001, we conducted five line-transect surveys in conjunction with camera-trap surveys. Density estimates of calling males varied from 0.4 to 2.5 males km−2, and the total density estimate ranged from 0.9 to 3.7 birds km−2. Density estimates increased substantially between 1998 and 2001, reflecting recovery from depressed densities after the 1997-1998 El Niño drought. Habitat occupancy estimates varied from 25% to 38% but were not significantly different over time. The proportion of occupied habitat was similar to the proportion of habitat I. We conclude that Great Argus Pheasants prefer undisturbed forest and rarely use other habitat even as population density increases. Restricted movements and habitat preference may limit the ability of Great Argus Pheasants to colonize forest fragments.