Irruptive dynamics of invasive carnivores and prey populations, and predator control, affect kea survivorship across the Southern Alps

Kemp, Joshua R.; Young, Laura M.; Mosen, Corey; Bolitho, Liam; Orr-Walker, Tamsin; Yockney, Ivor; Elliott, Graeme

doi:10.1080/03014223.2021.2021249

Cited by 5 publications

(10 citation statements)

References 42 publications

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“…On the drier eastern side of the Southern Alps, kea live mostly in beech (Nothofagus sp.) forests (Joshua R Kemp et al, 2023). A study using whole genome data estimated pre-human kea numbers to be fairly stable, averaging about 23,000 individuals (Martini, Dussex, Robertson, Gemmell, & Knapp, 2021).…”

Section: Historymentioning

confidence: 99%

“…), and cats (Felis catus). The only known native extant predator of kea is the New Zealand falcon, karearea (Falco novaeseelandiae), which has been seen attacking adult kea (Jackson, 1969) but is only known to be successful at predating juveniles (Joshua R Kemp et al, 2023). Mosen, Elliott, Hunter, & van Klink, 2019), and show high fidelity to certain nest sites, where they often have multiple burrows, the female selecting and preparing a cavity from among them each year (Mitchell, 2022).…”

Section: Historymentioning

confidence: 99%

“…Mosen, Elliott, Hunter, & van Klink, 2019), and show high fidelity to certain nest sites, where they often have multiple burrows, the female selecting and preparing a cavity from among them each year (Mitchell, 2022). These cavities may be gaps under boulders, crevices, spaces under tree roots or inside hollow logs (Jackson, 1963) and are usually found between 600 and 1200m above sea level (Joshua R Kemp et al, 2023). A narrow, well-worn track often leads up to kea burrows (G. R. Marriner, 1909), which are often in openings in the canopy made by slips or rocky outcroppings (Jackson, 1963).…”

Section: Historymentioning

confidence: 99%

“…Masting causes a spike in mouse numbers resulting in a spike in predator numbers the following year. Most years kea populations are capable of maintaining the high levels of adult survival needed for population persistence (likely > 90%), without 1080 control (Joshua R Kemp et al, 2023). However, in post-mast (irruption) years, the crash in mouse numbers results in prey switching by stoats.…”

Section: Predationmentioning

confidence: 99%

“…However, in post-mast (irruption) years, the crash in mouse numbers results in prey switching by stoats. This was recently found to reduce adult kea survival in eastern ecosystems to around 77% (Joshua R Kemp et al, 2023). The authors predict that, given their frequency, if masting events are unmanaged, eastern kea populations will go extinct (Joshua R Kemp et al, 2023).…”

Section: Predationmentioning

confidence: 99%

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Captive trials of a potential predator exclusion device for kea (Nestor notabilis) burrows and analysis of burrow monitoring footage.

Ireland

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Kea (Nestor notabilis) are a declining endemic New Zealand parrot. Most estimates place their current population at around 6,000. This thesis focuses on three aims to inform future kea conservation: 1) Investigating the potential of installing flaps on wild kea burrow entrances to exclude predators, 2) Developing and detailing methods to efficiently process kea burrow monitoring footage, 3) Using the processed data to characterize the activity of kea and their predators at burrows.For Aim 1, trials were conducted with captive kea to establish whether they could pull open a flap to gain access to a space containing rewards. Captive kea interactions with flaps set to open outwards only were observed and analysed. Two kea were able to pass through already open flaps and pull closed flaps open. However, neither passed through flaps after they themselves pulled them open, which appeared to be due to an aversion to having the flap rest on their back when passing through. These observations suggest that flap designs similar to those used as pet doors are unlikely to be suitable for predator exclusion from wild kea nests. Interactions of predators with a flap in a wetland were also investigated.For Aim 2, footage obtained over six breeding years at seven nesting locations was provided by the New Zealand Department of Conservation (DOC) the Kea Conservation Trust and community groups. This dataset comprised 1,585,044 images. I developed a new approach to streamline image tagging, which grouped images into sessions of animal activity, so that only a single image from each session required manual tagging to identify the species present. This approach resulted in a 97.77% reduction in the number of images needing manual tagging, with a corresponding estimated loss of only 3.29% of the total occurrences of animal activity.Using this dataset for Aim 3, I found that the most common predator species captured on the monitoring footage were possums (196 sessions) and weka (165 sessions). Activity of weka, rats, stoats and possums increased at the start of kea nesting in July. All predators were largely nocturnal except stoats and cats. Predator visits outside as well as inside burrows were generally short (less than 30 seconds). Stoats in particular rarely stayed longer than this. The majority of burrow predation appears to have been of eggs, with only six of 24 chicks seen in nests likely not to have fledged. Overall nesting success from the 19 burrow seasons of monitoring was low, with an estimated 18 chicks fledging.The data highlight the need to maintain current efforts to reduce the impact of predators on kea and develop improved methods of protecting kea burrows

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Section: Historymentioning

confidence: 99%

Section: Historymentioning

confidence: 99%

Section: Historymentioning

confidence: 99%

Section: Predationmentioning

confidence: 99%

Section: Predationmentioning

confidence: 99%

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Captive trials of a potential predator exclusion device for kea (Nestor notabilis) burrows and analysis of burrow monitoring footage.

Ireland

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Pitfall trapping outperforms other methods for surveying ground-dwelling large-bodied alpine invertebrates

Bertoia,

Murray,

Robertson

et al. 2023

J Insect Conserv

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Appropriate sampling methods are essential for monitoring and managing all wildlife. There is limited information on how to monitor ground-dwelling invertebrates in the alpine zone compared to more commonly studied lower-elevation habitats. We aim to understand the strengths, weaknesses, and cost-effectiveness of invertebrate survey methods when deployed in the alpine zone. We tested four methods on the South Island of New Zealand (Aotearoa): pitfall traps, tracking tunnels, visual surveys, and trail cameras. We focused on methods for ground-dwelling large-bodied invertebrates, a group most likely to be impacted by introduced mammalian predators. Pitfall traps and trail cameras were practical methods for surveying alpine invertebrates. Tracking tunnels only reliably detected large wētā (Orthoptera: Anostostomatidae), as other invertebrates were too light to leave distinguishable tracks. Visual surveys did not generate enough observations to be considered a successful method. We found no difference in the total abundance or easily recognised taxonomic groups detected by pitfall traps and trail cameras. Trail cameras detected fewer wētā compared to tracking tunnels and pitfall traps. Of the successful methods, pitfall traps were the most cost-effective, followed by tracking tunnels and trail cameras. Tracking tunnels were the fastest to install and required the least processing time, followed by pitfall traps and trail cameras. We recommend using pitfall traps to survey large-bodied alpine ground-dwelling invertebrates to better understand population trends or community composition. This method was consistent across all alpine habitat types and has the potential to be an effective method to inform conservation monitoring and management programmes. Implications for insect conservation Monitoring is vital to understand how invertebrates respond to change and evaluate conservation management program outcomes. This study provides practical information on potential monitoring tools for invertebrates in the alpine zone and recommends pitfall traps to survey large-bodied alpine invertebrates.

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From the lab to the wild: how can captive studies aid the conservation of kea (Nestor notabilis)?

Bastos

Nelson

Taylor

2022

Current Opinion in Behavioral Sciences

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Irruptive dynamics of invasive carnivores and prey populations, and predator control, affect kea survivorship across the Southern Alps

Cited by 5 publications

References 42 publications

Captive trials of a potential predator exclusion device for kea (Nestor notabilis) burrows and analysis of burrow monitoring footage.

Captive trials of a potential predator exclusion device for kea (Nestor notabilis) burrows and analysis of burrow monitoring footage.

Pitfall trapping outperforms other methods for surveying ground-dwelling large-bodied alpine invertebrates

From the lab to the wild: how can captive studies aid the conservation of kea (Nestor notabilis)?

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