These same patterns of endemism hold strongly among reptiles and amphibians in the philippines (Alcala and Brown 1998), where endemism percentages can run even higher than among the nonflying mammals. Bats and birds show similar patterns to herpetofauna but with some interesting differences. The places where endemic species occur are similar. but the percentage of endemism is much less: usually 10-20 percent rather than 40-80 percent (Heaney 1991b; Stattersfield et al. 1998). The reasons seem clear: animals that are able to fly can maintain gene flow across permanent sea channels whereas nonflying animals cannot (Peterson and Heaney 1993). Thus, birds and bats are diverse and widespread, but greater degrees of isolation are needed to form distinct species than among the nonflying mammals, reptiles, or amphibians. lnvertebrates such as butterflies in this region show patterns similar to those of birds and bats, confirming the observations based on vertebrates (Holloway 1987, 1998).