During the first week in January, 1908, few rats were seen, but their numbers increased gradually, until in March and April they were plentiful.
In June rats were very numerous about our camp in Denham Bay, being seen frequently in the daytime, but more especially in the evenings, when they invaded our whares.* They searched everywhere for food, but did not gnaw into any of our boxes. Although naturally timid, they would explore every part of the whare if we kept quite still, and, as soon as the light was out, jump up on the table near which two of our party slept, and would sometimes even run over us as we lay in our bunks. We poisoned them periodically with arsenic, but it merely checked their numbers for a few days, after which they appeared as numerous as ever.
As showing the large number of rats that exist on Sunday Island, the following figures are given on the authority of Mr. R. S. Bell. He estimated that in three years 44,000 were killed by poisoning and other means, while on one occasion 173 were caught in a single night near the cultivations in Denham Bay by means of a trap made with a harbour-buoy.
The rats decreased in numbers during July. In August, on wet evenings but few were to be seen, but on fine nights a fair number came about our whares. During September and October very few were noticed.
That the rats disappear into the ground during the summer months seems certain, for on one occasion Mr. R. S. Bell accidentally dug out one of their burrows and discovered a number of rats which appeared somewhat sleepy and dazed on being turned out into the daylight. During their out-season they usually retire to their holes in the daytime; when surprised in the forest they immediately make for their burrows and disappear. It is probable that they breed in the ground, as young ones were noticed chiefly at the end of summer.
Their food consists principally of fruits. Bananas, oranges, passions, grapes, and figs all disappear before hordes of rats, and the settlers on Sunday Island must protect their fruit-trees if they wish to have any share of the fruit. A piece of tin nailed round the stem at a distance of about 2 ft. from the ground will prevent rats from climbing the tree, but bananas must be cut just as the first signs of yellow begin to appear in the fruit, and placed in some position where rats are unable to get at them.
Sunday Island rats are not strictly frugivorous, but, on the contrary, will eat any kind of food. Birds and their eggs, when they are to be obtained, are eaten, also the flesh and fat of goats, while specimens of rats I had gathered for examination when thrown out were usually devoured by their own kind. The beaches were constantly searched, and any fish or other animals cast up by the sea eaten by rats.
[Footnote] * Huts made of a framework of poles, with sides and roofs of rushes, palm-leaves, or banana-leaves.