<I>Mus musculus</I>

We document an increase in house mouse (Mus musculus) abundance in a year (2002) when there was light beech (Nothofagus species) seedfall but very heavy rimu (Dacrydium cupressinum) seedfall in Waitutu Forest, southern New Zealand. On our nine study grids, mouse numbers in November were highly correlated with rimu seedfall. Feeding trials with wild-caught captive mice showed that mice typically opened the rimu nut and ate the seed (endosperm and embryo) leaving the husk.

A single five night pulse of sodium monofluroacetate (0.15% 1080) applied in bait stations at two different spacing intervals, 100 and 200 m, along forestry roads in New Zealand beech forest, killed all four of the resident radio-tagged stoats (Mustela erminea) and all three of the resident radio- tagged wild house cats (Felis catus) by secondary poisoning. Gut contents of predators indicated that house mice (Mus musculus), ship rats (Rattus rattus) and bushtail possums (Trichosurus vulpecula) were important sources of the toxin.

Eradication of rodent species from some offshore islands has proved to be an effective means of conserving native animal communities and restoring natural ecological processes on the islands. As methods of eradication differ fur different rodent species, a truthful monitoring method to detect species presence and relative density is essential for a successful eradication programme.

Over five years from November 1982 to November 1987, we examined 395 mice collected from unlogged and logged native forest and from exotic forest at Pureora Forest Park, in the central North Island of New Zealand. Sex ratio, litter size, and breeding effort (pregnancy rate in females, proportion of males with visible tubules) were similar in all samples.

The objective of this study was to quantify the population dynamics, morphological characteristics, and diet of rodents on Rangitoto Island (Hauraki Gulf, New Zealand) to provide information for the future development of an eradication strategy. An aerial 1080 operation to eradicate possums and wallabies was carried out two months after the study began. The effects of this operation on rodent population dynamics are discussed. Both ship rats (Rattus rattus) and mice (Mus musculus) were trapped on Rangitoto Island over a 15 month period.

This paper describes the impact of nine poison operations on ship rats in four areas (35 ha to 3200 ha) of North Island forest. Poisoning with 1080, brodifacoum, or pindone killed 87- 100% of rats, based on trapping and tracking-tunnel indices. Rat populations took 4-5 months to recover. Operations to protect nesting birds should therefore coincide with the onset of nesting and be rePeated each year, although not necessarily with the same methods.

Changes in density and breeding of the house mouse (Mus musculus) in a New Zealand forest dominated by hard beech (Nothofagus truncata) were monitored for 2.5 years. Mice bred during winter and increased dramatically in density only during a beech mast year. Mice readily ate the endosperm and embryo of hard beech seed in die laboratory and chemical analysis showed it to be a very nutritious food source, similar in quality to Fagus beech seed in the northern hemisphere.

The prevalence of infestation of the skulls of stoats with the parasitic nematode Skrjabingylus nasicola was previously described in a national survey by King and Moody (1982). Since then, more samples from Craigieburn Forest Park and from the Eglinton Valley, Fiordland, have been collected, and a method of determining the actual ages of adult stoats has been developed. The extended samples are here examined for a relationship between infestation and age, which could not previously be tested. Prevalence generally increases with age, significantly so at Craigieburn.

Adele (87 ha) and Fisherman (3.6 ha) Islands lie 800 m and 1100 m, respectively, offshore in Tasman Bay, Nelson. Both are covered predominantly in native forest and scrub. There are mice (Mus musculus) on Adele Island but no rodents on Fisherman Island. Both islands are within swimming range of stoats (Mustela erminea) which have colonised Adele Island and occasionally visit Fisherman Island, 700 m distant.

Efficient detection techniques will confirm the presence of a species at a site where the species exists, and are essential for effective population monitoring and for assessing the outcome of management programmes. However, detection techniques vary in their ability to detect different species. A wide range of mammalian predator species, most introduced into New Zealand since the late 18th century, have had a detrimental impact on the native flora and fauna.