Australian Field Ornithology 2016, 33, 97–101 http://dx.doi.org/10.20938/afo33097101

Presence and breeding of the Spiny-cheeked in

central

John Rawsthorne

Research Institute for Environment and Livelihoods, Charles Darwin University, Darwin NT 0909, Email: [email protected]

Abstract. The seasonal presence and breeding of the Spiny-cheeked Honeyeater Acanthagenys rufogularis, a nomadic frugivorous distributed across inland Australia, are documented and contrasted for three nearby but floristically distinct sites in central New South Wales during the period January 1986–January 2015. Eucalypt blossom at two of the sites (Charcoal Tank and Holy Camp) provided an autumn resource to which the Spiny-cheeked Honeyeater responded with influxes, but these sites supported limited breeding of this , and only in higher-rainfall periods. In contrast, the high density of Grey Mistletoe quandang parasitising Weeping Myall pendula at the third study site (Battery Hill) provided a stable resource supporting breeding resident Spiny-cheeked in a lower-rainfall year.

Introduction Battery Hill intermediate between the two. The Battery Hill site centres on a roadside strip (18.8 ha) of uninterrupted Arid-adapted nomadic present an intriguing Weeping Myall with heavy infestation of set of questions and challenges regarding life-cycle Grey Mistletoe (~900 mistletoes per requirements: when and where to breed and what to do hectare), with the surrounding area consisting variously of in the meantime. These apparently simple questions are cleared farmland, and mixed woodland strips and patches difficult to answer for Australia’s inland birds. The bias containing Grey Box microcarpa, Blakely’s in the study of the breeding biology of Australian birds Red Gum E. blakelyi and Black Cypress-pine towards sedentary species and temperate climates (Clarke endlicheri (Rawsthorne 2007). There is no understorey 1997; Shine & Brown 2008) means that the constraints that shrub layer at the Battery Hill site. Charcoal Tank Nature dictate presence and breeding of nomadic birds in more- Reserve is 86 ha and features long-unburnt Broombush arid environments are poorly known. The ‘boom-and-bust’ Melaleuca uncinata–Green Mallee E. viridis–Blue Mallee patterns that apply to waterbirds, finches and Budgerigars E. polybractea shrubland and also Mugga Ironbark Melopsittacus undulatus are partly known (Robin et al. E. sideroxylon–Grey Box–Black Cypress-pine woodland 2009). Rainfall is an important breeding cue for inland communities (NSW NPWS 2011). It is set within a matrix birds (Keast & Marshall 1954; Stevens & Watson 2006; of agricultural land and remnant patches of woodland. Burbidge & Fuller 2007; Shine & Brown 2008; Recher & The Holy Camp study area (~45 ha) lies on the lower Davis 2014). However, studies of avian response to rainfall east-facing slope of the Weddin Mountains, within an events in inland Australia have yielded weaker associations extensive area of mixed woodland situated on shale soil. between rainfall and presence or abundance of frugivores The canopy is variously dominated by White Box E. albens, and nectarivores, compared with other avian guilds (Pavey Grey Box, Mugga Ironbark, Blakely’s Red Gum and Black & Nano 2009; Tischler et al. 2013). Cypress-pine, with an understorey of Hopbush Dodonaea The Spiny-cheeked Honeyeater Acanthagenys rufogularis is one such nomadic frugivore/nectarivore of Australia’s arid interior. In this account, I describe and contrast the presence and breeding activities of this species at three nearby sites with distinctly different habitats near the south-eastern edge of its range in central New South Wales (NSW). The contribution of mistletoe as a factor moderating the effects of rainfall variability on presence and breeding of the Spiny-cheeked Honeyeater is considered.

Methods

Study sites Data were collected at three sites in central NSW (Figure 1, all within 50 km of 33°48′S, 147°30′E). Although geographically close, the three sites have distinct flora, with annual rainfall varying from 475 mm at West Wyalong (Charcoal Tank) to 621 mm at Grenfell (Holy Camp), with Figure 1. Location of the study sites in New South Wales. 98 Australian Field Ornithology J. Rawsthorne

viscosa, tending to open grassland in some areas. In contrast with the heavy mistletoe infestation at the Battery Hill site, the Charcoal Tank and Holy Camp sites have sparse infestation of Box Mistletoe Amyema miquelii and Fleshy Mistletoe A. miraculosa.

Study species Number of captures The Spiny-cheeked Honeyeater is a mid-sized (~50 g) . It is present in a range of drier woodland and scrubland habitats and landforms throughout mainland Australia, except for the tropical north and parts of the east Month and south-eastern coastal strip. The species has a varied Figure 2. Monthly variation in number of Spiny-cheeked diet including arthropods, fruit and nectar (Higgins et al. Honeyeaters trapped at two long-term banding sites in 2001), with mistletoe fruit and nectar featuring heavily in its central NSW, showing a significant peak in captures in diet in some contexts (Reid 1990; Recher & Davis 1997). autumn and winter, and a near-complete absence of the species in the more easterly site (Holy Camp) in spring The Spiny-cheeked Honeyeater is noted as resident or and summer (Rayleigh’s test for circular uniformity: Holy nomadic in different parts of its range (Keast 1968; Higgins Camp z = 266.1, P <0.001, n = 391; Charcoal Tank z = 99.1, et al. 2001). It is a breeding resident species in many P <0.001, n = 939). Acacia/mistletoe woodland systems in arid Australia (Reid 1990; Cody 1994; Recher & Davis 1997). It is also present in a range of eucalypt woodlands and other scrublands but combinations of colour bands and individually numbered is often described as a blossom nomad in these habitats metal leg bands. This allowed individuals to be identified (Higgins et al. 2001). in the field. Eight of these colour-banded birds had radio- transmitters fitted, which also allowed movement paths to The age of individual Spiny-cheeked Honeyeaters be recorded. Movement data were collected over a 3-week can be distinguished based on the colour of short spine period in spring 2006 (Rawsthorne 2007; Rawsthorne feathers on their cheeks: individuals with fully white spines et al. 2011). Individual radio-tracked birds were observed are known to be at least in their second year of life, but for a minimum of 8 h in bouts of 1–2 h, with individual those with any yellow colouring in their facial spines are birds followed and their location and behaviour recorded no older than 2 years (Higgins et al. 2001). Sex has been continuously during the observation period. determined for breeding aviary birds of this species based on incubation behaviour, with only the female incubating eggs (Higgins et al. 2001). Analysis To test for seasonality in the Charcoal Tank and Holy Data collection Camp capture data, the distribution of trapping effort and captures by month were considered as circular data sets Bird-banding studies have operated at the Charcoal Tank and Holy Camp sites continuously since 1986, with the and tested for departure from a uniform distribution using sites subject to mist-net trapping and bird banding about Rayleigh’s test for circular uniformity (Zar 1999). five times each year over that time, covering all months of the year. Individually numbered metal bands were fitted to Results birds; presence of a brood-patch (scored 0–3, after Lowe 1989) was recorded for most birds. Data presented here In total, 391 Spiny-cheeked Honeyeater captures cover banding during the period July 1986–January 2015. (including 75 retraps) occurred at Holy Camp. Captures The Battery Hill site was surveyed for bird presence/ were seasonal (Rayleigh’s test, z = 266.1, probability absence each month during 2006. During October– P <0.001, n = 391), with 87% of captures over the study November 2006, Spiny-cheeked Honeyeaters at Battery period occurring during May–July (Figure 2), although the Hill were trapped in mist-nets and banded with individual number of captures differed from year to year (Figure 3). At Number of captures

Year

Figure 3. Number of Spiny-cheeked Honeyeaters trapped at two long-term banding sites in central NSW, showing variation in presence from year to year. Spiny-cheeked Honeyeater, central New South Wales 99

the Charcoal Tank site there were 939 captures (including Clarke 2002). This same autumn–winter peak is evident in 128 retraps). Spiny-cheeked Honeyeaters were captured in eucalypt woodland at Charcoal Tank, where the dominant all months, although with a similar late autumn–winter peak eucalypt nectar source is Mugga Ironbark, but a few in captures (Figure 2) (Rayleigh’s test, z = 99.1, P <0.001, Spiny-cheeked Honeyeaters were also captured in spring– n = 939) and inter-year variations (Figure 3). Trapping summer at this more westerly site (Figure 2). The seasonal effort was not seasonally biased at either site (Rayleigh’s influx of the species trapped at the two long-term banding test: Holy Camp z = 1.30, n = 121, not significant; Charcoal sites was a mix of immature and adult birds. Tank z = 0.11, n = 151, not significant). Site-fidelity for Spiny-cheeked Honeyeaters was low Twenty-one percent of Spiny-cheeked Honeyeaters at the two eucalypt woodland sites (Charcoal Camp and captured at Holy Camp were retrapped during the study Holy Camp), and lower than for sedentary bird species period, with ten birds (3%) retrapped >1 year after original at the same sites. For example, 23% of Brown-headed capture. At Charcoal Tank, 12% of captures were retrapped Honeyeaters Melithreptus brevirostris captured at Holy at least once, with 38 birds (5%) retrapped >1 year after Camp over the period 1986–2009 were retrapped initial capture. >1 year after initial capture (Rawsthorne 2014), and post- There were no records of heavily vascularised brood- 1-year retrap rates for other known resident species at patches on Spiny-cheeked Honeyeaters at Holy Camp the site include White-plumed Honeyeater Lichenostomus in the 29-year study period, and no nests of the species penicillatus (15%), Speckled Warbler Chthonicola have been observed at Holy Camp in this time (Richard sagittata (25%), Rufous Whistler Pachycephala rufiventris Allen pers. comm.). In 29 years of observation at (13%), Grey Shrike-thrush Colluricincla harmonica (15%) Charcoal Tank, only one Spiny-cheeked Honeyeater and Eastern Yellow Robin Eopsaltria australis (27%) nest was recorded (Mark Clayton pers. comm.), and (JR unpubl. data). The equivalent retrap rates of ≤5% there were six captured individuals of this species with for Spiny-cheeked Honeyeaters at both eucalypt well-developed brood-patches (score 2 or 3), in each woodland sites in this study are comparable with case following above-average rainfall in the preceding other non-resident species at Holy Camp such as 2% 4 months. for each of Yellow-faced Honeyeater Lichenostomus chrysops and Rainbow Bee-eater Merops ornatus (JR Of ten Spiny-cheeked Honeyeaters banded at the Battery unpubl. data). Nomadic or partly migratory species Hill site in spring 2006, five showed evidence of recent or might show high fidelity to breeding sites (e.g. Noisy current breeding, following below-average rainfall in the Friarbird Philemon corniculatus: Ford 1998; Painted preceding 4 months. Two nests with incubating pairs were Honeyeater: Barea & Watson 2007; Rainbow Bee-eater: identified at the Battery Hill site, both placed within dense JR unpubl. data), but given the variable nature of winter mistletoe clumps ~3 m above the ground. Only one bird food resources (particularly eucalypt blossom) in south- from each of these pairs—presumed to be the female— eastern Australia, low inter-annual return rates are to had a brood-patch when examined in the hand, with the be expected for blossom nomads in the two eucalypt presumed male having no brood-patch and not seen to woodland sites. incubate eggs during the observation period. Spiny-cheeked Honeyeaters occasionally remained Other bird species showing indications of breeding within beyond winter and bred at Charcoal Tank, but only in wetter or near the mistletoe patch at the Battery Hill site in spring periods. This is similar to the rainfall-mediated breeding 2006 included Dicaeum hirundinaceum response of woodland birds in the eucalypt-dominated (juvenile being attended and fed by adults), Singing Great Western Woodland in Western Australia (Recher Honeyeater Lichenostomus virescens (nest with two & Davis 2014) and Warrumbungles farther north in NSW nestlings found) and Grantiella picta (Stevens & Watson 2006, 2013). Aggressive competitive (seen carrying nesting material, but no active nests or exclusion by abundant resident White-plumed Honeyeaters juveniles observed). at the two eucalypt woodland sites may tend to exclude Spiny-cheeked Honeyeaters from these habitats in periods Discussion when resources are scarce (Pavey & Nano 2009). The Spiny-cheeked Honeyeater’s low site-fidelity, and some Variations in presence in eucalypt woodland over long absences and infrequent breeding at just one of the time—blossom nomadism eucalypt sites, suggest that, apart from the autumn nectar resource, the eucalypt-dominated habitat mostly provides The seasonal variation in Spiny-cheeked Honeyeater a weak resource base for this species. presence in eucalypt woodland at Holy Camp (Figure 2) is consistent with a more general influx of honeyeaters to the A high-quality Acacia woodland resource site during autumn and winter associated with eucalypt— supports a sedentary population particularly White Box—flowering (Rawsthorne 2014; R. Allen pers. comm.). It is also consistent with observed In contrast with the two eucalypt woodland study sites, winter influxes of Spiny-cheeked Honeyeaters on the at the Acacia woodland at Battery Hill some individual north-western and eastern edges of this species' range in Spiny-cheeked Honeyeaters were observed within their the Tanami Desert (Northern Territory/Western Australia) breeding territories at the site throughout the observation and NSW Hunter region (Keast 1968; Tarrant 2008). period October 2006–July 2007. Moreover, the species Although there was a strong seasonal pattern to presence was recorded in monthly surveys at the site and floristically at Holy Camp, the species did not appear every year similar Acacia sites within 100 km in every month (Figure 3), and the movement pattern is best described as from January to December 2006, whereas aggressive nomadism rather than migration (Keast 1968; Griffioen & competitors such as White-plumed Honeyeaters were 100 Australian Field Ornithology J. Rawsthorne

mostly absent from these Acacia woodlands (JR unpubl. rainfall (Ehleringer & Marshall 1995), meaning that periods data). of high or low rainfall have delayed and/or dampened impacts on mistletoe fruit and nectar availability. Thus The main resource at the Battery Hill site was Grey frugivores of Australia’s interior should not be expected to Mistletoe, which provided a year-round supply of fruit respond quickly to rainfall events, and will also remain in and/or blossom and associated invertebrates, and dense dry areas while mistletoe fruit remains. clumps of foliage that were used by Spiny-cheeked Honeyeaters for nesting. In a similar mistletoe-infested Acacia woodland system near Whyalla in South Australia, Acknowledgements Reid (1984) found that individuals of this species defended The long-term banding studies at Charcoal Tank and Holy Camp breeding territories continuously for >2 years. Mistletoe have been co-ordinated by Mark Clayton and Richard Allen, fruit may also be used as a water source, allowing birds to respectively, since inception. Mark, Richard, and all volunteers persist in otherwise dry areas (Walsberg 1975). Although that assisted at these sites over time are acknowledged and Spiny-cheeked Honeyeaters often visit water (Reid 1984; heartily thanked. I thank Stuart Rae for assistance with circular JR pers. obs.), none of those in the Battery Hill study was statistics. The Battery Hill fieldwork relied on the efforts of Terry seen to visit any water source during the radio-tracking Korodaj, Len Reitsma, Mike Hallworth, David Roshier, and Kim Rawsthorne, and was financially supported by the Winifred Violet period in October 2006, despite the temperature often Scott Trust. Harry Recher and David Watson provided invaluable exceeding 25°C, and reaching 32°C on 1 day during the feedback on an earlier version of this manuscript. The Charcoal radio-tracking period. Movements of incubating pairs of Tank and Holy Camp studies operated under NSW National Parks Honeyeaters in this study were wholly contained within and Wildlife Service Scientific Licences SL100825 and SL100990 small (<0.5 ha) patches of mistletoe-bearing Acacia, respectively. The Battery Hill study was operated under NSW and tracking records show that individuals of incubating National Parks and Wildlife Service Scientific Licences S10906 pairs did not leave the small home-range (Rawsthorne and S11890 and Care and Ethics Committee protocol et al. 2011), and incubating females rarely left the nest. 06/093 issued by the Charles Sturt University Animal Care and Ethics Committee. 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