Preliminary report on damage to coconuts and on the ecology of the Polynesian rat (Rattus exulans) in the Tokelau Islands

Extensive trapping shows that the Polynesian rat (Rattus e. exulans (Peale)) is the only rodent present in the Tokelau Islands and that it is responsible for damage to coconuts. Green coconuts 5-25 cm. long are gnawed on the palms and subsequently fall to the ground and disintegrate. Damage was assessed by counting damaged and undamaged nuts in quadrats on various islets of the Nukunonu and Atafu atolls. The numbers of rats on these islets were assessed by using the capture-mark-recapture method. It was found that mature, untended and overgrown islets showed severe damage but had a low rat population. On the other hand, equally mature but relatively well-tended groves carried a much heavier rat population but showed no damage to coconuts.