Introduced mammalian predators, in particular rats (Rattus spp.), are a major threat to New Zealand bat populations. Aerial application of the toxin sodium monofluoroacetate (1080) is currently the most costeffective method of controlling rats across large spatial extents. Lesser short-tailed bats (Mystacina tuberculata) may be vulnerable to secondary poisoning from 1080 because they feed on invertebrate prey on the ground that may have consumed toxic bait.
From eight trials made during 1967-69 a technique was developed for estimating the reduction, by poisoning, of opossums (Trichosurus vulpecula) from the extent of interference with non-toxic flour-paste baits. The model assumes that opossums do not, through experience and learning, search for other baits close by.
The trial data showed that contagion, an increase in levels of bait interference from night to night and very high acceptance levels were a consequence of baits having been preferentially placed on open ridges and spaced too closely.
The effects of an aerial 1080 possum poison operation using carrot baits on invertebrates in Whirinaki Forest Park are described from an un-replicated study of artificial refuges attached to tree trunks. Auckland tree weta (Hemideina thoracica), cave weta (Pharmacus sp.
Five-minute bird counts were made on Rangitoto Island in 1998 and 1999, 8 and 9 years after the start, and 1 and 2 years after the completion of a 7-year programme that resulted in eradication of the introduced brushtail possum (Trichosurus vulpecula) and brushtailed rock wallaby (Petrogale penicillata). These were compared with counts made in 1990 (immediately before the start of the programme), to assess whether bird species diversity and abundance had increased as a result of the eradications. The number of bird species detected in 1998/99 was similar to 1990.
This study aimed to estimate the level of mortality of North Island tomtits (Petroica macrocephala toitoi) during an aerial 1080 possum poisoning operation in Tongariro Forest, New Zealand, and to evaluate transect-based alternatives to banding for monitoring tomtit populations. The operation used 12 g toxic (1080 at 0.15% weight/weight) cereal baits sown at 3 kg/ha. Transects were established at three neighbouring sites; two within the 1080 poison area, and one outside.
Aerial poisoning operations with carrot or cereal baits are used to control brushtail possum (Trichosurus vulpecula) populations in New Zealand forests for ecosystem conservation and to stop the spread of bovine tuberculosis to cattle and deer herds on adjacent farmland. Although various measures have been implemented to reduce the incidence of bird kills, dead birds continue to be found after poison operations.
Lesser short-tailed bats (Mystacina tuberculata) feed on arthropod taxa known to consume 1080 baits. Thus, they may be vulnerable to secondary poisoning after control operations for brushtail possum (Trichosurus vulpecula) using aerially broadcast 1080 baits. Short-tailed bat mortality was monitored during 11 days after 1080 baits were broadcast over their winter foraging area. Monitoring involved catching a sample of 269 bats as they arrived at a roost after foraging, then holding them in captivity for 48 hours.
Toxins, especially sodium monofluoroacetate (1080) and brodifacoum, are widely used throughout New Zealand for control of introduced mammals that are considered pests. This level of toxin use (not necessarily with these toxins) is unlikely to decline for at least 5-10 years. Ecological consequences derive both from mammal population reduction or eradication, and from using toxins as the control method.
Assays for the toxin sodium monofluoroacetate (compound 1080) were undertaken on arthropods collected from toxic baits after a brushtail possum (Trichosorus vulpecula) control operation in Nothofagus forest in central North Island, New Zealand. The 1080 concentrations measured (mean 57 mu g per g, max 130 mu g per g) are considerably higher than those reported by other researchers who collected arthropods randomly after control operations.
The results of a programme to monitor the containment and natural breakdown of approximately 12 000 kg of toxic vertebrate pest bait, containing compound 1080 (sodium monofluroacetate), in a landfill site are reported. The baits were buried in a purpose-dug pit in a managed solid waste disposal site at Winton in central Southland, New Zealand, in August 1996. Compound 1080 is used extensively in a bait form to control a range of introduced vertebrate pests, (e.g., European rabbit, Australian brush tailed possum), which cause considerable economic and environmental damage in New Zealand.