DOI: 10.5061/dryad.8gtht76r3
title: Data from: Controlling trapping, overgrazing and invasive vegetation is key to saving Java's last population of the Black-winged Myna

description: The Black-winged Myna (Acridotheres melanopterus) is an Endangered
 passerine endemic to the islands of Java and Bali,
 Indonesia. Illegal trapping to supply the cage-bird trade has led
 to its near-total extinction, with the global population estimated to
 number fewer than 100 individuals. The only known population of
 Black-winged Mynas on Java occurs at Baluran National Park (BNP). These
 data were generated to meet the two primary aims of the linked paper: the
 first was to estimate the Black-winged Myna (Acridotheres melanopterus)
 population size and range at BNP; and the second was to use species
 distribution modelling to evaluate the potential suitability of areas
 currently unoccupied by Black-winged Mynas across BNP to identify
 priorities for management intervention. We carried out line-transect
 distance sampling following the standard distance analysis method to
 estimate the population size. A total of 56 detections of groups of
 Black-winged Mynas were recorded along line transects and are included in
 the dataset. These records are associated with the land cover type for
 that segment of the transect, the perpendicular distance of the record to
 the transect, and the survey effort associated with each transect. To
 produce the species distribution model, we used three predictor raster
 layers along with all Black-winged Myna presences recorded (not
 freely available, see below) and a generated set of pseudo-absences. The
 dataset contains both the raw data used to create the land cover
 classification as well as the final raster. The raw data used to produce
 the habitat classification contains classified points (n = 426) from
 across BNP, which were used as a training and test data for a random
 forest land cover classification.
description: Supervised land cover
 classification We have provided the raw
 data used as the input for a supervised land cover classification. During
 fieldwork, the observer visited points around the national park and
 classified them into one of eight broad land cover types (open savanna,
 savanna woodland, dry deciduous woodland/shrubland, dry deciduous forest,
 thorny acacia scrub, teak plantation, tropical evergreen forest, beach
 forest, and mangrove forest). This gave 221 classified points. To increase
 the sample size of the classes with fewest classified points, there are an
 additional 205 points that were classified using Google Earth image
 interpretation. For a detailed description of the land cover types adopted
 here, please see Supplementary Material Table S1. The data are recorded in
 the UTM zone 50S coordinate system. Distance
 analysis The raw data used to produce the
 population size estimate are provided. However, all location data have
 been removed. These data were collected using the standard line transect
 distance sampling method. A detailed description of the method used is
 provided in the Methods section of the associated paper. Birds seen in
 flight were not recorded, but those seen taking off or landing were
 recorded to that position. For detections where group size was unknown, we
 used the average group size for all known groups. During post-processing,
 transects were split into segments based on land cover type, which was
 taken from our supervised land cover classification. Sampling effort was
 then calculated for each transect segment. We included a 'habitat
 openness' covariate for analysis, for which open savanna and woodland
 savanna were considered 'open habitat' and woodland land cover
 types were considered 'closed habitat'. The headings in the
 table provided follow those required by package Distance in R. The units
 used for Effort are kilometres and area is measured in
 km<sup>2</sup>. The 'distance' is the perpendicular
 distance of the detection from the transect and is measured in
 metres. Habitat suitability
 analysis Due to the sensitivity of our
 study species, the coordinates for Black-winged Myna presences cannot be
 provided here. Bona fide researchers are welcomed to contact the
 corresponding author to request these data, which can be used with the
 three predictor layers provided to replicate the species distribution
 modelling procedure and determine potentially suitable habitat for the
 myna. The NDVI layer was calculated from the Landsat 8 image covering
 Baluran from 8 October 2018 (downloaded from https://earthexplorer.usgs.gov); the land cover classification layer was generated using our habitat data and we also developed a habitat openness layer from it, for which each pixel represents the proportion of open (open savanna or woodland savanna) vs. closed (all other woodland types) habitat pixels in the 0.56 km<sup>2</sup> (25 × 25) surrounding the target pixel.
description: The location of Black-winged Myna presences have not been
 included in the dataset because the species is Endangered and threatened
 by illegal trapping. Requests to access these data should be made to the
 corresponding author (tom.squires@stu.mmu.ac.uk).