Australian Field Ornithology 2017, 34, 12–17 http://dx.doi.org/10.20938/afo34012017 The range and habitat of the Kalkadoon Grasswren Amytornis ballarae Graham Harrington1,2*, Adam McKeown1 and Brian Venables3 1CSIRO Land & Water, PO Box 780, Atherton QLD 4883, Australia 2BirdLife Northern Queensland, PO Box 680, Malanda QLD 4885, Australia 3527 McCormack Street, Edge Hill QLD 4870, Australia. Email: [email protected] *Email: [email protected] Abstract. In this paper we discuss the results of the first comprehensive survey of the range and habitat of the Kalkadoon Grasswren Amytornis ballarae. This grasswren is of particular interest because (1) It is not classed as a Restricted Range Species by BirdLife International although we show that it occupies <50 000 km2; (2) This species lives in a fire- prone environment, and the habitat is unsuitable for at least 3 years after fire. The movement and fate of the birds in these circumstances is unknown; (3) It is sympatric with the Carpentarian Grasswren A. dorotheae over part of its range, raising questions about competition between the species; and (4) The spatial and behavioural separation from the closely related Dusky Grasswren A. purnelli is not well defined. In 2008 and 2009, we visited 195 locations in firescars of known age within the known range of the Kalkadoon Grasswren and played calls of Kalkadoon and Carpentarian Grasswrens at 6–10 sites in each, totalling 1491 survey sites. We encountered 81 groups of Kalkadoon Grasswrens. They showed a marked preference for metamorphosed sandstone and marble. They were almost always found on rocky hills, but if on flat areas they were within 300 m of hills. Spinifex Triodia spp. dominated the ground-layer at all the sites where Kalkadoon Grasswrens were located. Ground-cover by spinifex increased annually after fire and plateaued after 6 years. Kalkadoon Grasswrens had returned to 30% of 3- and 4-year-old firescars, but occurred in 90% of locations surveyed which had not been burnt for ≥10 years. No grasswrens were encountered in surveys between the currently published ranges of the Dusky Grasswren in the Northern Territory and the Kalkadoon Grasswren in Queensland. This paper provides a distribution map, and defines the habitat variables for the Kalkadoon Grasswren. Our mapping shows that the range of the Kalkadoon Grasswren is ~40 000 km2, which qualifies it as a BirdLife International Restricted Range Species. We argue that an Important Bird Area should be declared for conserving and monitoring this species alone, where it is not sympatric with the Carpentarian Grasswren. Grasswren are recorded here to enable a comparison with the description in Higgins et al. (2001). Introduction the Kalkadoon Grasswren. Habitat parameters for the The most important influence on the population size Kalkadoon Grasswren are recorded here to enable a of Kalkadoon Grasswrens is probably fire. Burning A proposal to declare an Important Bird Area (IBA) for the comparison with the description in Higgins et al. (2001). temporarily reduces the area suitable for the birds and Kalkadoon Grasswren Amytornis ballarae was rejected The most important influence on the population size of probably causes their death. It is not known to what extent by Dutson et al. (2009). The reasons given were that the Kalkadoon Grasswrens is probably fire. The area suitable 2 a) birds die by perishing in the flames, b) subsequently population was stable and occupied an area >50 000 km , for the birds is temporarily reduced by fire and many starve due to decrease and/or c) are more susceptible which meant that this grasswren could not be described probably die. It is not known to what extent birds (a) die by to increased predation due to reduced protective cover. as a Restricted Range Species. This decision was based perishing in the flames, (b) subsequently starve because of Felderhof (2007) found Kalkadoon Grasswrens in a few upon a mapped range (Stattersfield et al. 1998) that is decreased food availablility and/or (c) are more susceptible 3-year-old firescars but none in younger habitat. This larger than the area attributed to the Kalkadoon Grasswren to increased predation because of reduced protective paper seeks to establish the probability of the Kalkadoon by Schodde & Mason (1999) and Higgins et al. (2001). Our cover. Felderhof (2007) found Kalkadoon Grasswrens in a Grasswren occurring in fire scars of different ages as the decision to survey this species was partially based upon few 3-year-old firescars but none in younger habitat. This spinifex regrows and to define its range and habitat. the concern that this species is vulnerable to fire and the paper seeks to establish the probability of the Kalkadoon area of its distribution was not well defined. Grasswren occurring in firescars of different ages as the spinifex regrows and to define the range and habitat of the Methods Another reason for undertaking this survey was to test the published description of the Kalkadoon Grasswren’s species. habitat—that it is confined to areas where the ground- The area of study was chosen according to the reported layer is dominated by the hummock grass spinifex Triodia range of this species, which equated approximately to the Methods spp.; is usually found on rocky hillsides, ridges and gullies; Mount Isa Inlier bioregion (Schodde 1982; Higgins et al. occasionally in less-rugged terrain and with short spinifex; 2001). As we were not certain how far north or south this The area of study was chosen according to the reported but is never found on flat plains or river valleys (Higgins et species extended, we surveyed beyond the recorded range of this species, which equated approximately to the al. 2001). range.in a northerly and southerly direction. To the north Mount Isa Inlier bioregion (Schodde 1982; Higgins et al. we surveyed up to and including Boodjamulla (Lawn Hill) We were also interested in the spatial separation from 2001). As we were not certain how far north or south this National Park (latitude 18°3′S) and to the south as far as the closely related Dusky Grasswren A. purnelli, which is species extended, we surveyed beyond the recorded range Mount Unbunmaroo (latitude 22°5′S) (Figure 1). The main not well defined. When the Kalkadoon Grasswren was first in both northerly and southerly directions: to the north, survey occurred in May 2008, with some supplementary recorded in the vicinity of Mount Isa as late as 1966, it was we surveyed up to and including Boodjamulla (Lawn Hill) surveys in May 2009. We made two visits to Mt. named as a subspecies of the Dusky Grasswren (Condon National Park (latitude 18°18′S) and to the south as far as Unbunmaroo in March and July 2010 (Figure 1). In August- 1969; Schodde 1982), but later was given species status Mount Unbunmaroo (latitude 22°30′S) (Figure 1). The main September 2014 we extended the southern part of the based on plumage characteristics (Schodde & Mason survey occurred in May 2008, with supplementary surveys 1999). Horton (2011) indicated that the behaviour and in May 2009. We made two visits to Mount Unbunmaroo ‘jizz’ of the Dusky Grasswren also differ from that of in March and July 2010. In August–September 2014, Kalkadoon Grasswren range and habitat 13 The 2008 survey sites were chosen to achieve approximately equal numbers in fire-age classes of 3–10 years. Only firescars which occurred within 1 km of a track navigable by a 4-wheel-drive vehicle were selected. The standard survey consisted of 10 points at intervals of 200 m arranged along three sides of a square 600 m × 600 m. The square was set at least 300 m from the edge of the firescar to increase the chance that the birds encountered in the survey reflected the conditions in that firescar and not the boundary conditions between firescars of different ages. In some locations, it was not possible to set the survey points around a square because of impassable topography or the shape of the firescar; in such cases, the surveyors used their judgment to place the survey points within the firescar at intervals of 200 m, whilst maintaining the protocol of all survey points being at least 300 m from the edge of the firescar. At each survey point, the surveyors stood back to back and one played a standard recording of first Kalkadoon and second Carpentarian Grasswren A. dorotheae calls using an Mp3 player through 3-watt speakers. The calls used were obtained from Plowright (1994). After completion of the play-back procedure, the surveyors watched and listened for response from grasswrens for a further minute. If there was no such response, they switched positions and repeated the exercise. The play-back procedure was not initiated until both surveyors indicated that they Figure 1. The Extent of Occupancy (EOO) of the Kalkadoon were ready to watch and listen for a response from the Grasswren. Locations where Kalkadoon Grasswrens birds because such responses can be very short-lived (KGW) have been recorded in the surveys in this study and could be missed by an inattentive surveyor. If the and from the BirdLife Atlas are shown as black dots. White surveyors obtained a response, either visually or vocally, dots indicate where surveys did not encounter Kalkadoon they attempted to identify the species of grasswren, count Grasswrens. Triangles indicate where surveys were the number of birds in the group, assign the sex of the undertaken in 2014 on spinifex-covered hills to the south of the EOO. The Queensland–Northern Territory border is birds, and note from which part of the landscape the birds along the 138°E longitude. appeared (ridge, upper slope, lower slope, drainage line, rocks).