Currently our preliminary results show the
presence of high reproductive skew in Siamese
fireback and low reproductive skew in silver
pheasant. However, we are not yet able to
explain why this difference in mating system
occurs. As their home ranges appear too large
compared with their daily travel route
(Sukumal, unpublished data), the assumption
proposed by Mitani & Rodman (1979) for
territorial behaviour, for which animals should
travel a daily travel route long enough to
ensure the encounter of their territory boundary
at least once a day, can be rejected for both
species. We can exclude then that the factor
triggering this reproductive skew is to be found
in various levels of help needed by dominant
males in maintaining territories (Jamieson,
1997; Cockburn, 1998). Future work will focus
on investigating the risk of dominance take
over, together with the cost of a floater status,
for which both dominant males and subordinate
will need to “cooperate”. Furthermore, genetic
relationships among animals in the study area
are still completely unknown and thus the
inclusive fitness hypothesis proposed by Packer
et al. (1991) cannot currently be tested