The effect of aerially applied 1080 on the nesting success and survival of kākā

Kākā (Nestor meridionalis) are vulnerable to predation by stoats (Mustela erminea) and possums (Trichosurus vulpecula), particularly when nesting. Without predator control kākā populations decline. Control of stoats and possums both by trapping and aerial application of the poison 1080 leads to increased kākā nesting success. In recent years, many 1080 poison operations have been undertaken to control ship rat (Rattus rattus) and stoat plagues that occur after beech mast. Kākā do not breed every year but breed in anticipation of heavy fruiting.

Visual and taste cues for minimising native bird interactions with toxic 1080 baits – a review of current practices

Non-target risk from the use of vertebrate toxins for pest control is an ongoing issue globally. In New Zealand, toxic bait for aerial control of possums and rodents is dyed green and contains cinnamon oil, both of which are thought to reduce the risk that birds will eat the bait. It has been suggested for some time that blue dye may be a more effective feeding deterrent than green dye.

Impacts of introduced mammalian predators on New Zealand’s alpine fauna

Alpine zones are threatened globally by invasive species, hunting, and habitat loss caused by fire, anthropogenic development and climate change. These global threats are pertinent in New Zealand, with the least understood pressure being the potential impacts of introduced mammalian predators, the focus of this review. In New Zealand, alpine zones include an extensive suite of cold climate ecosystems covering c. 11% of the land mass. They support rich communities of indigenous invertebrates, lizards, fish, and birds.

Browse on mahoe and kamahi leaf-fall as a trigger for possum control

Introduced brushtail possums (Trichosurus vulpecula) are controlled over large parts of New Zealand to protect canopy trees. The condition of canopy trees is one of the cues used to trigger possum control, but selecting an indicator of canopy tree condition is difficult because many factors unrelated to possum browsing can affect canopy condition, and indices based on canopy scoring may not always quickly detect real changes in possum herbivory.

Possums as seed dispersers in New Zealand: A response to Williams (2003)

We agree with Williams’ (2003) response to our previous paper (Dungan et al., 2002) whereby data is presented in support of the contention that we overstated our argument that possums may be the only dispersal vector for large–seeded native New Zealand species. We contend that this does not alter our overall conclusions, but agree that additional work is needed to balance any potential positive effects of possums as seed dispersers against their significant negative impacts on forested ecosystems.

Are possums important dispersers of large-seeded fruit?

The claim by Dungan et al. (2002) that “in many areas possums may be the only potential dispersal vector for large-seeded native species” is unsubstantiated. There is little evidence possums excrete viable seed of large-seeded fruit greater than 10 mm diameter, and seeds up to this size are dispersed by a suite of bird species. Nowhere in New Zealand are there likely to be possums in the absence of this suite of bird species.

Mistletoe (Tupeia antarctica) recovery and decline following possum control in a New Zealand forest

The condition of 79 plants of the loranthaceous mistletoe Tupeia antarcticain a podocarp-hardwood forest in the central North Island, New Zealand, was monitored over 4 years during a period of increasing possum density, following previous possum control. Mistletoe comprised 1.2% of total possum diet during the three years following possum control. Incidence of possum browse on mistletoe plants increased from 2.6% of plants when the trap-catch index of possum density was < 3%, to 75.9% of plants when trap-catch rates reached 4.6%.

Microhabitat selection by feral ferrets (Mustela furo) in a pastoral habitat, East Otago, New Zealand

The spatial distribution of feral ferret (Mustela furo) activity and denning were studied using ink-print tracking tunnels and radio-tracking within pastoral farmland containing a mosaic of grazed (developed and semi-developed) and ungrazed pasture, scrub, tree plantation and scrubby fence lines at Palmerston, East Otago, South Island, New Zealand. Ferrets concentrated their activity in grazed areas but within these areas they were found more often where herbs, scrub and woody cover were present, and where there was an ecotone between pasture and vegetation cover.