Australian Field Ornithology 2014, 31, 17–23 Observations of the Striated Grasswren Amytornis striatus rowleyi at Opalton, central western Queensland K.A. Wood 8 Kalamunda Street, North Lakes QLD 4509, Australia Email: [email protected] Summary. Ninety-six records of the Striated Grasswren Amytornis striatus rowleyi (Rusty Grasswren A. rowleyi) were obtained during 14 visits to Opalton in central western Queensland between May 2009 and October 2012. Most records (35) were of groups with a minimum of two individuals (range 1–9+). Three calls are described: contact call, song and alarm. They were uttered throughout the day from first light to sunset. In 12 records, Striated Grasswrens were seen to fly, usually 30–40 cm above the ground over a median distance of 15 m (range 8–35 m). Groups of Striated Grasswrens were associated with Rufous-crowned Emu-wrens Stipiturus ruficeps in 15 records. Inquisitive behaviour is described, and other behaviours Forum— are compared with co-occurring Rufous-crowned Emu-wrens (34 groups) and Spinifexbirds Eremiornis carteri (19 individuals). Do Tasmanian Southern Boobooks migrate? Introduction The Amytornis grasswrens are among Australia’s most elusive and least known Jerry Olsen1* and S.J.S. Debus2 birds (Rowley & Russell 1997; Christidis et al. 2010). They are cryptic, shy and secretive (Pringle 1982; Chapman 1996; Karubian 2001) and mostly live in 1Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia remote parts of Australia. The north-eastern subspecies of the Striated Grasswren 2Zoology, University of New England, Armidale, NSW 2351, Australia A. striatus rowleyi is no exception. It was first collected near Opalton in 1970 Corresponding author. Email: [email protected] (Macdonald 1970), when it was identified as A. striatus. Subsequently, Schodde & Mason (1999) gave it subspecific status in 1999. Information on the behaviour of other subspecies of the Striated Grasswren (A. s. striatus and A. s. whitei) is given in Schodde’s (1982) monograph of the fairy-wrens and grasswrens, but the behaviour of A. s. rowleyi has not yet been reported. This paper attempts to fill some gaps in knowledge about the subspecies A. s. rowleyi. Such information could be important, given that A. s. rowleyi is genetically divergent from A. s. striatus (Christidis et al. 2010), and was explicitly elevated to species status as the Rusty Grasswren A. rowleyi (Christidis et al. 2013) at the time that this paper went to press. Data and information were collected during a wider investigation into the habitats used at Opalton between 2009 and 2012 (see Wood 2014). Ninety-six records are used to quantify and describe various aspects of behaviour. Study area The study area was centred on Opalton (23°15′S, 142°46′E), ~100 km south of Winton, where the landscape consisted of a variety of habitats and ecotonal areas situated in a series of low ranges (maximum altitude 270 m above sea-level). At higher altitudes (>260 m asl), caprock mesas were dominated by a sparse shrub layer of acacias and cassias under 18 Australian Field Ornithology K.A. Wood scattered Mountain Yapunyah Eucalyptus thozetiana (5–7 m tall). Scarps supported Lancewood Acacia shirleyi (7–9 m tall) on stony lithosols, sometimes closely packed without any understorey. The upper and lower slopes were gentle, dominated by Normanton Box Eucalyptus normantonensis low open woodland (4–6 m tall) and Gidgee Acacia cambagei low open woodland (5–7 m tall), respectively. Spinifex Triodia spp. covered about half of the study area, mostly on upper slopes and mesas. The study area has been described in greater detail elsewhere (see Wood 2014). Because the area has been extensively mined for opal since 1888 (McKenzie 2000), numerous eroded miners’ tracks and abandoned diggings are present. There has been no grazing by domestic livestock and there have been no major bushfires for at least 20 years (P. Gregory & A. Hubbard pers. comm. 2012). Methods Between May 2009 and October 2012, the study site was visited 14 times in either spring or autumn, except for one visit in August 2010. During these visits, ranging from 1 to 18 days (median duration 5.5 days), a total of 138.1 hours was spent searching for Striated Grasswrens. During these searches, I recorded one or more individuals on 96 occasions. A total of 40 separate groups was probably encountered (see Wood 2014). During the first and second visits, some birds or groups (n = 7) were followed for 20–40 minutes to become familiar with behavioural traits. Thereafter, most sightings (54 records) lasted 3–10 minutes, and birds were generally not followed. Because breeding was not confirmed by observing active nests or feeding of fledged young, these records can be classed only as non-breeding records. While searching for Striated Grasswrens, Rufous-crowned Emu-wrens Stipiturus ruficeps(34 groups) and Spinifexbirds Eremiornis carteri (19 individuals) were sometimes encountered. Striated Grasswrens, Rufous-crowned Emu-wrens and Spinifexbirds were watched for varying times with 8 × 40 Leica binoculars, and notes were entered in field diaries. Distances were stepped or estimated visually. Results and discussion Nature of encounter and distance from observer Striated Grasswrens were seen before they were heard in 43 records, heard before they were seen in 42 records, and flushed by car or observer in another 11 records. The median flushing distance was 12 m (range 3–22 m, n = 11). The median distance from the observer to the bird when first seen or heard was 25 m (range 8–35 m, n = 85). Number of birds Because of the secretive nature of the species and a priority to investigate the habitats during visits to the study site (Wood 2014), it was difficult to accurately count the number of birds in each group within the allocated time. Table 1 lists minimum numbers of Striated Grasswrens in each record. A minimum of two birds was encountered on 35 occasions (Table 1). The highest number of birds seen simultaneously was nine (possibly ten) in November 2010, when their calling and activity was indicative of two groups interacting with each other. Striated Grasswren behaviour, Opalton, Queensland 19 Table 1. The minimum number of Striated Grasswrens present in 96 records at Opalton, Qld, 2009–2012. Minimum number of birds per group 1 2 3 4 5 Number of times recorded 18 35 18 17 8 Time of day Most records (67 of 96, 70%) were in the early morning or late afternoon (Table 2). However, given that I searched and moved about mostly when it was coolest, it cannot be concluded from this study that the Striated Grasswrens were easier to see in the early morning or late afternoon than at other times. However, the Grasswrens at Opalton were active at all times during the day (contra Morcombe 2000), even around midday when temperatures were >35°C and they were sometimes seen thermoregulating with wings held partly open. Calls Three calls were recognised: contact call, song and alarm. The contact call see-see or see-see-see was regularly uttered by Striated Grasswrens out of sight, within or behind spinifex hummocks. It was very soft (almost inaudible in moderate wind) and very similar to the contact calls of the Rufous-crowned Emu-wren. Striated Grasswren song was unusual and diagnostic, audible from 30–40 m, and much louder than contact calls. In this study, it was generally perceived as a rippling wren-like reel, lasting up to 10 seconds, varying in pitch and consisting of whistles, buzzes, twangs and staccato notes. Song has previously been recorded at Opalton by G.S. Chapman [refer www.graemechapman.com.au (retrieved November 2012)]. Song was heard much less frequently than contact calls. Occasionally, song was uttered a few times by one bird if the group was observed (or listened to) for at least 5 minutes. Twice (August 2010 and September 2012), a Grasswren was observed singing from an exposed branch (30–40 cm from the ground) with its open bill pointing skywards (similar to the Striated Grasswren A. s. whitei in photograph in Pringle 1982, p. 96). In this study, single Striated Grasswrens were heard to utter an alarm call on 21 occasions. This call was harsh and usually comprised a series of single notes, Table 2. Time of day during which Striated Grasswrens were recorded in 96 records at Opalton, Qld, 2009–2012. Time of day Early Late morning Early Late morning (0900–1200 h) afternoon afternoon (<0900 h) (1200–1500 h) (>1500 h) Number of records 32 17 12 35 20 Australian Field Ornithology K.A. Wood each of which was transliterated as jit. Usually jit-jit or jit-jit-jit was heard (rarely one or four jits). The alarm call was invariably given when a Grasswren was flushed. Contact calling and song were given throughout the day from first light until dark. Between September and November, counter-calling of song by different birds was periodically heard around my camp between first light and sunset, whereas Schodde (1982, p. 155) stated that A. striatus males call and answer one another ‘throughout mid-morning and late afternoon as they advertise territory’. Locomotion Striated Grasswrens ran or hopped in the alleyways between spinifex hummocks in a series of fast jerky movements. During pauses to forage on lateritic gravel, they were well camouflaged. In four instances, Grasswrens jumped or flew over a spinifex hummock and landed out of sight on the remote side. Flight Twelve flights, all by single Striated Grasswrens, were seen. On three occasions, the birds flew when flushed, but otherwise they voluntarily flew while foraging. The median flight distance was 15 m (range 8–35 m). Ten of the flights were 30–40 cm above ground; the remaining two were ~1 m above the ground.