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PACIFIC SCIENCE, Vol. Ill, July, 1949 
lished a balance with these alien species, but 
the possible effects of the non-native forms on 
species not now extant can only be conjectured. 
Non-native mammals may well have altered 
the ornithological picture considerably. One 
mongoose ( Herpestes griseus ) was seen far up 
on Olokui, suggesting that the species, which is 
difficult to see in dense forest, is probably 
common. One rat seen high in a tree was col- 
lected and identified as Rattus rattus alexandri- 
nus. Others had been eating the bananas of a 
small cluster of plants hidden in the native 
forest. Even in 1907 Bryan found evidence that 
the mongoose was decimating the population of 
the ground-nesting dark-rumped petrel (Ptero- 
droma phaeopygia sandwich ensis) . The rat may 
also be a serious enemy of ground-nesting birds 
and of many tree-nesting forms as well, since 
it is a good climber. Pellets of the Hawaiian 
owl ( Asio flammeus sandwich ensis) made up of 
rat remains were found at and below the lower 
edge of the native forest. This native preda- 
tory bird, which has been known in recent 
years from unforested parts of Molokai, could 
rarely if ever obtain rats in the dense native 
growth of most of the mountain. Goats, al- 
though abundant on the lower open canyon 
sides, have penetrated the native forest less 
than one-fourth of a mile. Undergrowth, espe- 
cially of the uluhe fern ( Dicranopteris linearis ), 
seems to hinder their further ingress. The goat 
seen highest on the mountain was immediately 
below ohia lehua trees where we first observed 
apapanes and amakihis. Goats had not yet 
markedly altered the native trees at this eleva- 
tion, although the lower vegetation was much 
changed. 
Various native birds (white-tailed tropic 
bird, black-crowned night heron, wandering 
tattler, and golden plover) were seen in Wailau 
Valley, but no endemic passerines were ob- 
served. Introduced birds seen were the Chinese 
dove, the mynah, and the white-eye. Little 
native vegetation remains in the lower part of 
the canyon but good stands of native growth 
were encountered on the steep south wall. Apa- 
panes and amakihis were again seen here as 
Fig. 2. Forest on Olokui Mountain. Large-leaved tree at left is alani ( Pelea clusiaefolia ) . Fern in fore- 
ground is okupukupu ( Nephrolepis exaltata ) . Dr. Flarold St. John in foreground. 
