Nest Box Use by Yellow-Tailed Black-Cockatoos on Kangaroo Island, 2015 – 2023 

This dataset contains data on the use of nest boxes by yellow-tailed black-cockatoos on Kangaroo Island (binary response variable; 1 = used in a breeding season, 0 = not used in a breeding season) for nest boxes monitored between 2015-2017 and again in 2020-2023 and the year of monitoring. In addition to this, data was sourced via spatial analysis and remote sensing on the distance to mature Pinus radiata plantation, distance to banksia dominated habitat, and amount of native vegetation within a 10km radius to approximate human disturbance and fragmentation. The name of nest boxes is included, and each nest's spatial location can be identified by this name on a separate Kangaroo Island Landscape Board spatial dataset. The spatial location of nests has been withheld as they identify important breeding sites for endangered bird species. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. This data was collected through projects funded by the Australian Government and World Wide Fund for Nature Australia. 

This data was collected when monitoring the use of nest boxes, which were primarily installed for endangered glossy black-cockatoos, but are also used by other species. The aim of this dataset was to determine how frequently yellow-tailed black-cockatoos use nest boxes and factors that influence nest box use. 

Nest boxes were visually inspected using an infra-red camera mounted on a 16 metre extendable pole and species occupying nest boxes or using them for breeding were recorded. Our target species, yellow-tailed black-cockatoos were recorded, but also any other species observed in nest boxes. Nest boxes were checked once between October and December, then approximately monthly between January and July subject to access to sites. Therefore, successful nests were often observed at egg stage and then again once to three times as the nestling grew. If a nest-box was both available for use and regularly monitored in a given breeding season, the monitoring dataset was used to determine whether it had been occupied or not by yellow-tailed black-cockatoos that season. If a nest contained a female yellow-tailed black-cockatoo incubating an egg or a yellow-tailed black-cockatoo nestling at any stage during a breeding season, that nest was recorded as having been used that year (ie nesting attempt in that nest box confirmed).

The spatial location of nest-boxes were mapped as point features in ArcGIS version 10.6.1. Two plant species known to be foraged on frequently by yellow-tailed black-cockatoos on Kangaroo Island are native Banksia species, and the introduced Pinus radiata. A spatial layer of remnant native vegetation communities on Kangaroo Island was provided by the Department of Environment and Water, based on mapping undertaken by Ball and Carruthers (1998), and this was used to determine the location of banksia dominated vegetation on Kangaroo Island. Pine plantations on Kangaroo were also mapped as polygon features. For each nest-box the distance to the nearest pine plantation and the distance to the nearest patch of native vegetation that had Banksia listed as one of the dominant species was calculated in ArcGIS version 10.6.1. This was to measure the proximity of nest-boxes to two major potential food sources, which was recorded in kilometres. We also calculated the amount of remnant native vegetation in a 10km radius of each nest-box, to measure how modified the landscape was in the vicinity of each nest-box, and whether nest boxes were more likely to be used in highly modified landscapes which potentially contained fewer natural tree hollows. the amount of remaining native vegetation around each nest box was recorded as a proportion (value between 0 and 1).

Large-scale wildfires occurred on the island during the 2019-20 Australian bushfire season. Most of the plant species yellow-tailed black-cockatoos rely on for feeding (Pinus radiata, Banksia sp. and Hakea sp.) are serotinous, and the therefore drop their seed following a fire, making burnt areas unavailable for feeding until plants regenerate and produce seed again. Fire impacted forests are also more open and do not provide the same habitat qualities as unburnt forest. Therefore, for all habitat measurements we used the distance to, and amount of, unburnt vegetation and this varied between years due to the fire event. Data from 2015-2017 were from years pre-fire, and data from 2020-2023 were post fire, and the distance to pine plantations and Banksia dominated habitat varied for each nest box between those two time periods. To determine the areas impacted by fire, and remove them as available habitat post-fire, burn-severity mapping for the 2019-20 fires was undertaken by running a Normalised Burn Ratio (NBR) model using Sentinel-2 data with a 10 m resolution from a two-week period immediately before the fires (1-19 December 2019) and a two-week period post-fire (15 February-1 March 2020). The NBR model was run using Google Earth Engine (Gorelick et al. 2017; Google 2020). Near-infrared (NIR) and shortwave-infrared (SWIR) reflectance were calculated for both the pre- fire and post-fire Sentinel-2 imagery, and the change in NBR between the two time periods was used to represent the magnitude of burn severity using values recommended by the US Geological Survey (outlined by Lasaponara et. al 2018).