Lizard feet found intact in a stoat stomach during a University of Otago research project. Funnel trapping was also deemed unsuitable for monitoring the nationally critical white-bellied skink ( Oligosoma hōparatea) in the mid-Canterbury high country after two skinks (one a white-bellied skink) were killed in traps by mice.” A weasel was caught in a trap with the remains of two skinks, and the other four were killed by mice. “In 2020, trapping at a scenic reserve on the Port Hills above Christchurch was discontinued after two days when six skinks were found dead in traps (5% of the total catch). Predation of lizards has been seen or inferred from both types of traps on several occasions. mice and weasels), and access pitfall traps by squeezing under (e.g. Despite these measures, some predator species are able to enter funnel traps (e.g. Traps must be removed or closed when not in use. It is also recommended for pitfall traps that gap size between lid and substrate should be 10–20 mm. “When operational, traps must be checked daily and be fitted with covers to provide shade, and to prevent or reduce the risk of desiccation and predation. Funnel traps (also called gee-minnow traps), consist of a cylinder with a funnel inverted at one or both ends, so that it’s easy to get in but not out.
With pitfall traps, a container is dug into the ground so that its opening is flush with the substrate. Two different methods of live trapping are commonly used to catch lizards in New Zealand, pitfall traps and funnel traps. Image credit: Tim Park (Wikimedia Commons). Leptograpsus variegatus), as well as other lizards.” Additionally, non-mammalian predators of lizards include native or introduced birds (e.g. Possible mammalian predators of lizards confined in traps in New Zealand are rats (kiore, Norway rats and ship rats), mice, mustelids (weasels, stoats and ferrets), hedgehogs, brushtail possums, cats, and dogs. “While some species have become extirpated from their historical ranges where predatory mammals have been introduced, many skink species classified as ‘At Risk’ or ‘Threatened’ under the Department of Conservation (DOC) Threat Classification System co-occur with varying densities of mammalian predators. More awareness of the risk may lead to new ways of reducing it. Our rare skinks and geckos have enough challenges to survive – without us literally delivering them to predators on a plate! The extent of the risk probably depends on the density of predators at the study site, the trap design and how well the monitored species can defend themselves. In addition to presenting both ethical and methodological issues for ecologists, in some cases, predation of trapped animals may have implications for species conservation (e.g. dehydration, exposure, starvation, drowning and predation among captured animals), few examine predation upon trapped animals. “While several studies investigate the efficacy of different trapping methods and risks to captured animals (e.g. The first aimed to quantify the amount of bait (tinned pear) being removed while the second aimed to confirm that rodents were responsible.Īlthough predator harvesting at pitfall traps had previously been observed, the extent to which it happened was unknown. A second rat of unknown species was seen at the site at around 10am on 11 January.”Īs a result of these observations, two methods were used to assess predation of skinks at pitfall traps. polychroma, as this was the only species caught during the salvage) hanging laterally from its mouth, and quickly disappeared into the grass. When it emerged, the rat had a skink (likely O. Strong northerly winds likely prevented the rat becoming aware of the observer. norvegicus) was observed foraging in a pitfall trap and emerging after around 10 seconds. “At 2pm on 10 January 2019, a rat (possibly R. The Barber pitfall trap – essentially a plastic bucket buried in the ground.
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