pest control

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.

Dead birds found after aerial poisoning operations targeting small mammal pests in New Zealand 2003–14

In New Zealand, aerial poisoning with 1080 (sodium fluoroacetate) bait is widely used for control of introduced small mammal pests in remote or forested areas. However this practice is controversial, partly because of perceived risks to native fauna, particularly birds. That perception originally derives from substantial mortality of some native bird species in pre-1980 control operations, which prompted changes in baiting practice to mitigate most of the risk.

Effect of the addition of bird repellents to aerially applied 1080 baits on rat and possum abundance

One of the criteria for an effective bird repellent in a pest management context in New Zealand is that possum (Trichosurus vulpecula) and ship rat (Rattus rattus) kills remain high where repellents are used in poison baits. Repellents were used in baits applied within different treatment blocks as part of a large aerial 1080 operation in November 2013 near Haast on the West Coast of the South Island of New Zealand.

Stability of bird repellents used to protect kea (Nestor notabilis) during aerial 1080 cereal operations

Aerial poisoning with cereal bait containing 1080 toxin is known to pose a risk to the kea (Nestor notabilis), an endemic New Zealand mountain parrot. For a bird repellent to protect kea during such poisoning operations, it must be effective in bait for 4–12 weeks after the bait is manufactured, as this is when most aerial 1080 cereal operations take place. Two bird repellents have been shown to be effective with captive kea, d-pulegone and 9,10-anthraquinone.

Predator control improves nesting success in Waikato forest fragments

Predation at nests contributes importantly to current declines of New Zealand forest birds. We monitored the survival of natural and artificial arboreal nests in small forest remnants south-west of Hamilton, where ship rat (Rattus rattus) and possum (Trichosurus vulpecula) abundances were also being measured in Summer 2008/09. Artificial cup nests (N = 77) were placed in replicated blocks with and without pest control, in both December and January.

Responses of kukupa (Hemiphaga novaeseelandiae) and other birds to mammal pest control at Motatau, Northland

The kukupa or New Zealand pigeon (Hemiphaga novaeseelandiae) is gradually declining on the New Zealand mainland, due mostly to predation by introduced pest mammals including ship rats (Rattus rattus) and brushtail possums (Trichosurus vulpecula). We report on a co-operative project between Maori landowners, the Department of Conservation, and Manaaki Whenua–Landcare Research researchers to restore a Northland kukupa population and to examine kukupa nesting success in relation to pest abundance.

A case for multi-species management of sympatric herbivore pest impacts in the central Southern Alps, New Zealand

Five herbivorous introduced mammals are sympatric in the central Southern Alps. All of these species have the potential to affect conservation values, yet the Department of Conservation at present monitors and mitigates the impacts of only one. We outline ecological arguments for multi-species management of sympatric herbivore pest impacts and use the two- species system of sympatric thar and chamois to highlight the need for multi-species management of the central Southern Alps alpine pest community.

Controlling small mammal predators using sodium monofluoroacetate (1080) in bait stations along forestry roads in a New Zealand beech forest

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.

Risks to non-target species from use of a gel bait for possum control

The risks to non-target species of a newly developed bait containing either 0.15% 1080 or 0.6% cholecalciferol in a gel matrix were assessed. Very few of them ate gel bait. The safety of the gel bait is further enhanced by its placement in the purpose-designed bait station from which little spillage occurs, and which can be placed so that it is out of reach of most non-target animals. Comparative data show that nontarget species are considerably less susceptible to cholecalciferol than to sodium monofluoroacetate (1080).

Survival of brown kiwi (Apteryx mantelli) exposed to brodifacoum poison in Northland, New Zealand

Brown kiwi (Apteryx mantelli) in central Northland have been monitored for up to 32 months of sustained exposure to brodifacoum poison. The cereal baits were placed in bait stations to target brushtail possums (Trichosurus vulpecula). Annual survival of 55 radio-tagged adult kiwi in two poisoned forest patches has been high (95.9%), and similar to that in two nearby unpoisoned forest patches and in the patches before poison was used (95.3%).