Diet of mammalian predators in braided river beds in the central South Island, New Zealand

Murphy, Elaine; Keedwell, Rachel J.; Brown, Kerry; Westbrooke, Ian

doi:10.1071/wr03033

Cited by 39 publications

(36 citation statements)

References 17 publications

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“…Although there may still be variation in size of rabbits taken with males consuming more adults, and females more nestlings and juveniles (Ragg 1998), too few claws and teeth were found in scats to enable such comparisons to be made in our study. Studies from New Zealand have suggested some degree of difference between the sexes (Ragg 1998), while others found no difference or only minor differences (Mills 1994;Murphy et al 2004), the latter a finding mirrored in the polecat in Europe (Lode 2003). The lower occurrence of avian remains in scats in both seasons suggests that predation on birds is incidental, with ferrets continuing to seek out preferred lagomorph prey.…”

Section: Dietary Analysis and Prey Consumptionmentioning

confidence: 88%

“…In New Zealand, ferret population dynamics have been shown to be linked to rabbit numbers (Barlow and Norbury 2001), and severe reductions in rabbit availability through poisoning or disease can have dramatic impacts on ferret behaviour. For example, the release of RHD has had important effects on conservation management as near absence of rabbits after initial disease outbreaks resulted in increased itinerancy amongst animals (Norbury et al 1998) and in significant diet switching to often highly endangered secondary prey (Murphy et al 2004;Norbury and Heyward 2008). While this ability to switch to alternatives can cushion a predator population against reductions in their principal prey, the negative effects for alternative prey species are often severe (Sinclair et al 1998).…”

Section: Conservation Management Implicationsmentioning

confidence: 97%

“…It is therefore not surprising that most of the significant studies into feral ferret ecology and behaviour have been carried out in New Zealand (reviewed in Clapperton and Byrom 2005). Although these studies have consistently shown rabbits Oryctolagus cuniculus to be an important dietary component Communicated by H. Kierdorf (Murphy et al 2004;Clapperton and Byrom 2005), ferrets are opportunistic predators (Smith et al 1995), and their diet may vary according to the availability of prey. Consequently, they have been demonstrated to be a threat to a variety of ground and burrow nesting birds including shorebirds (Dowding and Murphy 2001;Keedwell et al 2002) and seabirds (Alterio and Moller 1997;Lyver 2000).…”

Section: Introductionmentioning

confidence: 98%

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The diet of an invasive nonnative predator, the feral ferret Mustela furo, and implications for the conservation of ground-nesting birds

2010

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Introduced carnivores have had a significant impact on the fauna of a number of countries, particularly on islands. In the British Isles, several offshore islands holding internationally important aggregations of seabirds and shorebirds support self-sustaining feral ferret Mustela furo populations, often as the top terrestrial predator. However, little is known about the interactions between ferrets and both native and nonnative prey in these locations. We examined the diet of feral ferrets on Rathlin Island, Northern Ireland. We determined the frequency of occurrence of prey items and constructed energetic models to determine their potential impact on both native and introduced prey. Rabbits Oryctolagus cuniculus occurred in 75% of scats, while birds, carrion, and brown rats Rattus norvegicus were important secondary items. There was little difference between the diets of males and females. Estimates of the energy requirements of the population at current, and with hypothetically reduced, rabbit availability revealed the potential for carrion to maintain the ferret population over winter. Management options could thus focus on reducing anthropogenic food sources as an immediate way of mitigating the threat to ground-nesting birds, while other strategies, including eradication, are considered.

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Section: Dietary Analysis and Prey Consumptionmentioning

confidence: 88%

Section: Conservation Management Implicationsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

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The diet of an invasive nonnative predator, the feral ferret Mustela furo, and implications for the conservation of ground-nesting birds

2010

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“…They have been recorded from sea-level to 3000 m (Collins & Charleston 1979). In lower altitude tussock grassland and braided riverbed habitats, lagomorphs (mainly rabbits (Oryctolagus cuniculus)) are cats' most frequent prey; with birds, rodents, invertebrates and lizards also consumed depending on their local availability (Murphy et al 2004;Gillies & Fitzgerald 2005). On Stewart Island, where lagomorphs are absent, ship rats are the primary prey of cats, regardless of their abundance, and birds are their main alternative prey (Harper 2005b).…”

Section: Catsmentioning

confidence: 99%

“…Invertebrates, particularly orthopterans and coleopterans, are commonly eaten by cats, especially kittens, though contribute little mass in cat diet overall (Gillies 2001;Harper 2005b). Some authors have suggested that in tussock grassland habitat, cats may consume more alternative prey such as invertebrates when rabbits or rodents are scarce, or when kittens have not yet developed the hunting skills to catch rabbits (Pierce 1987;Norbury et al 1998;Murphy et al 2004). In alpine habitat, short-horned grasshopper (Acrididae) remains have been identified in feral cat scats along Bealey Spur in Arthurs Pass National Park (K. Weston, pers.…”

Section: Invertebratesmentioning

confidence: 99%

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

O’Donnell¹,

Weston²,

Monks³

2017

NZ J Ecol

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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. Many taxa are obligate alpine dwellers, though there is uncertainty about the extent to which distributions of some species are relicts of wider historical ranges. The impacts of introduced mammalian predators are well described in many New Zealand ecosystems, though little is known about the impacts of these predators on alpine fauna. Here we review the importance of alpine habitats for indigenous fauna and the impacts of introduced mammalian predators; and develop a conceptual model explaining threat interactions. Most evidence for predation is anecdotal or comes from studies of species with wider ranges and at lower altitudes. Nevertheless, at least ten introduced predator species have been confirmed as frequent predators of native alpine species, particularly among birds and invertebrates. In the case of the endangered takahe (Porphyrio hochstetteri) and rock wren (Xenicus gilviventris), stoats (Mustela erminea) are primary predators, which are likely to be impacting significantly on population viability. We also document records of mammalian predation on alpine lizards and freshwater fish. While the precise impacts on the long-term viability of threatened species have not been evaluated, anecdotal evidence suggests that predation by mammals is a serious threat, warranting predator control. Future research should focus on predicting when and where mammalian predators impact on populations of indigenous fauna, furthering our understanding of the alpine predator guild particularly through adaptive management experiments, and exploring interactions with other threats.

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Modeling habituation of introduced predators to unrewarding bird odors for conservation of ground‐nesting shorebirds

Latham

Anderson

Norbury

et al. 2018

Ecological Applications

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Foraging mammalian predators face a myriad of odors from potential prey. To be efficient, they must focus on rewarding odors while ignoring consistently unrewarding ones. This may be exploited as a nonlethal conservation tool if predators can be deceived into ignoring odors of vulnerable secondary prey. To explore critical design components and assess the potential gains to prey survival of this technique, we created an individual‐based model that simulated the hunting behavior of three introduced mammalian predators on one of their secondary prey (a migratory shorebird) in the South Island of New Zealand. Within this model, we heuristically assessed the outcome of habituating the predators to human‐deployed unrewarding bird odors before the bird's arrival at their breeding grounds, i.e., the predators were “primed.” Using known home range sizes and probabilities of predators interacting with food lures, our model suggests that wide‐ranging predators should encounter a relatively large number of odor points (between 10 and 115) during 27 d of priming when odor is deployed within high‐resolution grids (100–150 m). Using this information, we then modeled the effect of different habituation curves (exponential and sigmoidal) on the probability of predators depredating shorebird nests. Our results show that important gains in nest survival can be achieved regardless of the shape of the habituation curve, but particularly if predators are fast olfactory learners (exponential curve), and even if some level of dishabituation occurs after prey become available. Predictions from our model can inform the amount and pattern in which olfactory stimuli need to be deployed in the field to optimize encounters by predators, and the relative gains that can be expected from reduced predation pressure on secondary prey under different scenarios of predator learning. Habituating predators to odors of threatened secondary prey may have particular efficacy as a conservation tool in areas where lethal predator control is not possible or ethical, or where even low predator densities can be detrimental to prey survival. Our approach is also relevant for determining interaction probabilities for devices other than odor points, such as bait stations and camera traps.

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Diet of mammalian predators in braided river beds in the central South Island, New Zealand

Cited by 39 publications

References 17 publications

The diet of an invasive nonnative predator, the feral ferret Mustela furo, and implications for the conservation of ground-nesting birds

The diet of an invasive nonnative predator, the feral ferret Mustela furo, and implications for the conservation of ground-nesting birds

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

Modeling habituation of introduced predators to unrewarding bird odors for conservation of ground‐nesting shorebirds

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