August 28,
1964
(cont.)
traps when checked.
The roof rats were very large and strong.
Their general condition was very good.
Of the 8 sexually mature
females,
2 were pregnant
(both had early pregnancies)
3 had been pregnant previously.
Ten of the 12 males caught were sexually mature.
One of the
sexually immature males caught was large enough to be sexually
mature.
This phenomenen, which had been observed in several of
the population,
could be the result of intense population pres-
sure,
Roof rats seem generally distributed over the island in considerable numbers.
Why reproduction is occurring here and not
on some of the other reasonably comparable sites is not clear.
Norway rats were not found,
to be here.
bution
though they might be expected
Their colonial habits might have produced a distri-
pattern which would have been missed by the sampling pro-
cedure used.