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

Abstract

<p><strong>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.</strong></p><p>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.</p><p>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.</p><p>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.</p><p>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</p>