The effects of single aerial 1080 possum-control operations on common forest birds in the South Island, New Zealand

We used a long-term replicated before-after control-impact (BACI) sampling design to monitor the effect of aerial 1080 possum-control operations on common forest bird populations. Paired treatment and non- treatment sites in the Rolleston Range (East Coast, South Island) and Alexander Range (West Coast, South Island) were monitored once before 1080 treatment during winter 2012 and for three successive summers afterwards. Mammals (possums Trichosurus vulpecula, rats Rattus spp.

Short-term influence of snow cover on movements and habitat use by brushtail possums (Trichosurus vulpecula)

Climatic events affect the behaviour and ecology of many mammal species (e.g. activity, body condition, home range sizes or predation risk within others). We investigated short-term changes in movements, activity and habitat use of brushtail possums (Trichosurus vulpecula) in response to two major snowfall events in a grassland ecosystem in the southern South Island of New Zealand during winter of 2011. Global positioning system collars were deployed on 21 possums.

Habitat use and movements of the opossum (Trichosurus vulpecula) in a pastoral habitat on Banks Peninsula

The habitat use and movements of a population of Australian, brush-tailed opossums, Trichosurus vulpecula (Kerr), were studied by live-trapping, spotlighting and radiotelemetry in a mixed pasture, bush and scrub habitat on Banks Peninsula, New Zealand. Resident opossums had distinct ranges that for some animals varied in position and size and, for all, varied in intensity of use of habitat types during the year. Seasonal foods and breeding behaviour were reasons for shifts in ranges and changes in their sizes.

Autumn food of the brush-tailed opossum, (Trichosurus vulpecula [Kerr]) in the Otari Reserve, Wellington.

The stomach contents of 34 opossums collected from Otari reserve, Wellington, New Zealand, were examined and fragments of leaves and leaf cuticles were identified. Leaves were the main food though flowers, fruit and at least one insect were also taken. The main species eaten were kohekohe (Dysoxylum spectabile), pohuehue (Muehlenbeckia australis), hinau (Elaeocarpus dentatus), climbing rata (Metrosideros fulgens), five-finger (Pseudopanax arboreum), tawa (Beilschmiedia tawa) and lawyer (Rubus cissoids)

Effects of forest edges on herbivory in a New Zealand mistletoe, Alepis flavida

This study examined how forest edges influenced leaf and floral herbivory, as well as seed predation, in a native New Zealand mistletoe species, Alepis flavida. Plants growing on forest edges and in forest interior were compared, and effects of plant size and the neighbouring conspecific plant community were also examined. Leaf herbivory by possums was significantly greater on forest edges than in forest interior in a year of high possum damage, but not in a year with low damage levels. Insect leaf herbivory did not differ between forest edges and interior.

Possum (Trichosurus vulpecula) diet in a mast and non-mast seed year in a New Zealand Nothofagusforest

The annual diet of possums (Trichosurus vulpecula) during both a beech (Nothofagus) mast fruiting year and a non-mast year in the simple beech forests of the North Branch of the Hurunui Catchment, eastern South Island, New Zealand, was determined by sorting the contents of 270 possum stomachs, collected between December 1999 and December 2001. Beech flowers and seeds contributed 46.1% to annual diet during the mast year, but were not eaten during the non-mast year. Beech foliage and bark made up 13.2% and 45.0% of annual diet in the mast and non-mast years, respectively.

Effects of possums and rats on seedling establishment at two forest sites in New Zealand

Introduced rodents and possums in New Zealand eat flowers, fruits, seeds and seedlings, but little is known about their impact on forest regeneration. We investigated seedling establishment in exclosures with mesh of two different sizes to exclude (1) possums and (2) possums and rats, at two mainland forest sites (beech–podocarp–broadleaved and second-growth broadleaved–podocarp) near Dunedin. We recorded all new woody seedlings that established over the next 2 years.

Possum (Trichosurus vulpecula) control benefits native beech mistletoes (Loranthaceae)

The Australian brushtail possum (Trichosurus vulpecula) has been blamed for the decline of three native New Zealand beech mistletoe species (Alepis flavida, Peraxilla tetrapetala and Peraxilla colensoi, Loranthaceae), but there are few quantitative data on possum effects, and anecdotal evidence is often conflicting. We present results from two monitoring programmes that suggest possum control operations can improve mistletoe health.

Methods for monitoring herbivory and growth of New Zealand mistletoes (Loranthaceae)

This study provides the first quantitative comparison of methods for monitoring herbivory and growth of New Zealand beech mistletoes (Alepis flavida, Peraxilla colensoi and Peraxilla tetrapetala). Four monitoring methods-leaf maps, volume estimates visual estimates of browse and foliage density, and rePeat fixed-point photographs-were used to assess the health of 60 permanently tagged mistletoe plants in four South Island beech forests between February 1997 and February 1998.

New technology for poison delivery

A long-life poison bait dispenser, consisting of a tree-mounted platform that dispenses a highly attractive liquid bait only when triggered by actions characteristic of a possum (Trichosurus vulpecula), was developed. The liquid bait formulation prevents deterioration due to the action of oxygen, moisture, bacteria and insects. The prototype is designed to dispense 100 lethal doses of poison, and is expected to last more than five years in the field without attention. The equipment is designed to avoid fouling by algae, debris or nesting insects.