Australian Field Ornithology 2018, 35, 21–29 http://dx.doi.org/10.20938/afo35021029 Spring bird communities of a high-altitude area of the Gloucester Tops, New South Wales Alan Stuart1 and Mike Newman2 181 Queens Road, New Lambton NSW 2305, Australia. Email: [email protected] 272 Axiom Way, Acton Park TAS 7021, Australia. Email: [email protected] Abstract. Annual spring surveys between 2010 and 2016 in a 5000-ha area in the Gloucester Tops in New South Wales recorded 71 bird species. All the study area was at altitudes >1100 m. The monitoring program was carried out with involvement of a team of volunteers, who regularly surveyed 21 1-km transects, for a total of 289 surveys. The study area was within the Barrington Tops and Gloucester Tops Key Biodiversity Area (KBA). The trigger species for the KBA listing was the Rufous Scrub-bird Atrichornis rufescens, which was found to have a widespread distribution in the study area, with an average Reporting Rate (RR) of 56.5%. Another species cited in the KBA nomination, the Flame Robin Petroica phoenicea, had an average RR of 12.6% but with considerable annual variation. Although the Flame Robin had a widespread distribution, one-third of all records came from just two of the 21 survey transects. Thirty-seven bird species had RRs >4% in the study area and were distributed across many transects. Of these, 20 species were relatively common, with RRs >20%, and they occurred in all or nearly all of the survey transects. Introduction shrubs such as Banksia species (Binns 1995). These two habitats occur as a mosaic throughout the study area, with A high-altitude part of the Gloucester Tops in New South some sections of Snow Gum E. pauciflora open woodland Wales (centred at 32°05′S, 151°36′E) was surveyed also present (Binns 1995). The Antarctic Beech rainforest annually in spring over the period 2010–2016. The is characterised by an open understorey of ferns and Gloucester Tops form the eastern part of the Barrington Bracken Pteridium esculentum, whereas the eucalypt Tops National Park. In 2009, they were included in a newly forests have a dense understorey of Lomandra species, designated Important Bird Area (IBA), the Barrington Tops Bracken, fallen timber and leaf-litter. Mostly, the vegetation and Gloucester Tops IBA, on the basis of the presence of within the study area is dense and impenetrable, but there seven species: Rufous Scrub-bird Atrichornis rufescens, are several roads and walking tracks, which collectively Green Catbird Ailuroedus crassirostris, Regent Bowerbird sample all the key aspects of the area (e.g. following water Sericulus chrysocephalus, Australian Logrunner Orthonyx courses, steep slopes and ridges). temminckii, Paradise Riflebird Lophorina paradiseus, Twenty-one 1-km transects were established along Flame Robin Petroica phoenicea, and Pale-yellow Robin existing roads and tracks in the survey area. Figures 1–2 Tregellasia capito (Dutson et al. 2009). More recently, IBAs show their general location; individual transects are listed have been redesignated as Key Biodiversity Areas (KBAs) in Table 1. The 1-km segments were measured either in order to extend the concept to non-avian threatened by odometer readings where car access was possible, species (BirdLife Australia 2017). The boundaries and or by measurement on Google maps (https://maps. general location of the Barrington Tops and Gloucester google.com.au/) to determine end-point map coordinates Tops KBA are presented in Figure 1, which also shows (see Newman et al. 2014 for additional detail). Twenty the area covered in the present study. All of the study transects were surveyed annually in 2010–2012, with area was at altitudes of >1100 m. It should be noted that one additional transect (GT3A) added in 2013, and then a considerable part of the KBA is at lower altitudes and, all received regular survey effort in 2013–2016. In 2015 based on pilot surveys conducted contemporaneously with and 2016, because of resource constraints, the monitoring this study, has different bird assemblages. program was reduced, to focus on 11 of the 21 transects The main focus was to locate Rufous Scrub-bird (the five Kerripit Road transects, the five Gloucester Tops territories, and the study area historically was known to Road transects and the first kilometre of the Careys Peak contain core habitat for this species (see detailed results transects). in Stuart & Newman 2018). However, all bird species Each surveyed 1-km transect was visited at least encountered during the surveys were recorded and are four times each spring, except for the second and third presented here. Analysis of results from the 2010–2016 kilometres of the Mount Nelson Track and the final transect survey has led to insights about the bird population of this of the Careys Peak Track, which were more difficult to high-altitude part of the Gloucester Tops. access and thus were visited only two–three times each year. All 21 transects contained the two main Gloucester Methods Tops habitat types, Antarctic Beech rainforest and eucalypt open forest, although the ratio of these varied. Transects Two main habitat types occur in the study area, CP2 and MN2 were predominantly Antarctic Beech characterised by their principal types of vegetation: rainforest with some pockets of eucalypt open forest. Antarctic Beech Lophozonia moorei rainforest, and open Transect CP3 had only some small pockets of rainforest. eucalypt forest comprising mainly Messmate Eucalyptus Surveys were carried out by volunteers between obliqua and Brown Barrel E. fastigata interspersed with September and November annually. The timing coincided 22 Australian Field Ornithology A. Stuart & M. Newman Figure 1. Barrington Tops and Gloucester Tops Key Biodiversity Area and the study area (shaded). with the breeding season for Rufous Scrub-birds, when calling males are most reliably detectable (Ferrier 1984). The 1-km transects were surveyed by one–three people (typically two people) with at least one person being experienced in the survey method. Surveys were done only when conditions were favourable (low–medium wind, zero–low rainfall). They commenced c. 0800 h and took 4–6 h to complete. Typically, c. 1 h was spent in each transect; the actual time varied, depending on whether any Scrub-birds were located (because the surveyors were collecting additional specific information in such cases). Transect CP1 received extra coverage because of some visits to train new volunteers in Scrub-bird call recognition and to place and retrieve a Song Meter (Stuart et al. 2012). Surveyors recorded the presence of all bird species seen or heard along each 1-km transect, including any birds flying over (although extensive canopy cover limited the opportunities for the latter). No limit was set for the maximum distance from the track for records; under favourable conditions, a calling Rufous Scrub-bird can be heard 150 m away (Ferrier 1984) but for many other species the transect’s sampling width would have been less than that. For three sets of transects (Careys Peak, Glowang, Mount Nelson) the surveys involved two passes through each 1-km transect, i.e. outbound and then inbound a few hours later. Less time was devoted to surveying during the inbound passage and the total time spent in the transect remained c. 1 h. When surveyors had to return through a transect, they were asked to combine the records for both Figure 2. Locations for the transects in the Gloucester the outbound and inbound passages. The resulting data Tops study area (from Newman et al. 2014). Bird communities in spring, Gloucester Tops, New South Wales 23 were submitted to the BirdLife Australia Atlas (Birdata) as CP5, but this transect included all the species with overall 500-m-radius area surveys. Reporting Rates (RRs) for each RR >20%. This transect was surveyed only nine times. species for each year from 2010 to 2014 inclusive were Annual changes to the RR of regularly occurring species then calculated, and also for the 5-year period 2010–2014 (RR >4%) were analysed using only the first 5 years of and the 7-year period 2010–2016. The RR is the number data (2010–2014); because the survey effort was scaled of times the species was recorded divided by the number down in 2015 and 2016, data from the 2015–2016 surveys of surveys conducted (expressed as a percentage). were not used. Table 4 shows the RR in each year for 2010–2014 for these 37 species and the Coefficient of Results Variation (CV; often termed the relative standard deviation). From 2010 to 2016, a total of 289 surveys was carried out in the 21 1-km transects, recording 71 bird species. Discussion The cumulative number of species seen over the 7-year period is presented in Figure 3, and Figure 4 shows the The overall RRs of individual species (Table 3) indicate cumulative number of species in relation to survey effort, how often a species was recorded during the surveys. For which varied from year to year as already discussed. each species, the magnitude of the overall RR reflects a Table 1 summarises the results for each of the 21 transects, combination of its abundance, how widely it is distributed and Table 2 summarises the annual and overall results. (as indicated by the percentage of transects reported in Table 3), its ease of detection (i.e. large or vocal versus Seventy-one species were recorded in the spring surveys; small or cryptic) and variations in its annual occurrence the complete list of species is provided in Appendix 1. (Table 4). Thirty-four species had fewer than five records each and, in most of those cases, there were only one–three records. The cumulative number of species recorded increased With some exceptions, which will be addressed in relevant rapidly to 52 during the first 2 years of the study sections below, those species can be considered vagrant (Figure 3).