Day roost of Little Pied Bat Chalinolobus picatus (Gould) (Microchiroptera: Vespertilionidae) in north inland New South Wales, Australia Michael Pennay1 and Jade Freeman2 New South Wales Department of Environment and Conservation, PO Box 211 Dubbo NSW 2830. [email protected] [email protected]. Key words: Little pied bat, Chalinolobus picatus (Microchiroptera: Vespertilionidae), tree hollow roost, Pilliga West State Forest. The Little Pied Bat Chalinolobus picatus is listed as a The roost vulnerable species in NSW under the Threatened Species The roost tree was a large, living Bimbil Box tree Conservation Act (1995). Very little is known of its roost Eucalyptus populnea ssp. Bimbil, approximately 600 mm in habits, however it has been assumed that it roosts in trees diameter at breast height with several hollows of which because it is often captured in areas where caves are the bats were observed using two. These two hollows were absent (Ayres et al. 1996). This assumption is supported both similar in external size and position on the tree with by observations by Schulz et al. (1994) of C. picatus using the exception of aspect; one opening was on the western a tree hollow after release in Queensland and a radio- side (marked “a” in fig. 1), and the other on the north tracking study in the South Australian mallee where eastern side of the tree (marked “b” in fig. 1). several tree roosts were recorded by Dominelli (2000). Both hollows had an opening of approximately 20cm This note describes observations of a day roost used by C. diameter, the hollow entrances were caused by breakage picatus from the eastern part of its range near Wambadule of dead limbs, the break having formed a spout in the flora reserve in the Pilliga West State Forest, northern remaining part of the limb. Both limb spouts were at inland NSW (30º32’ 05” S, 148º40’ 20” E). angles slightly greater than horizontal. Both hollows were Several bats were observed in flight by the authors at approximately 10-15 metres above ground - emerging midday on the 9th December 2003 whilst driving through immediately above the midstratum layer of predominantly Pilliga West State Forest; the temperature was 36º C. Wilga Geijera parviflora and immature White Cypress Once stationary, we were easily able to identify the bats as Callitris glaucophylla. C. picatus by their distinct black and white markings and small size. Approximately 10 individuals were observed flying in loose circles around a large tree. The bats were seen flying into and out of two hollows on either side of this tree. After a period of about 2 minutes all of the bats had flown into the hollows and did not re-emerge, although ‘chattering’ could still be heard from both holes. Figure 1. The roost tree (Eucalyptus populnea ssp. bimbil), with arrows indicating the entrances to the hollow spouts used by Figure 1. Its distinctive black and white pelage and small size Chalinolobus picatus (A, western facing. B, north east facing). easily identify the Little Pied Bat Chalinolobus picatus. Photographs: Michael Pennay. Australian 166 Zoologist volume 33 (2) December 2005 Dec05.indd 166 14/02/2006, 10:08 PM Day roost of the Little Pied Bat The roost tree was estimated on visual observation to Although the tree we observed was still living, the actual be one of the largest mature trees scattered sparsely branches used were dead. throughout this part of the forest. This observation is Whilst it appeared that the bats were only departing and consistent with the pattern of selection for large trees alighting from the hollows in this single tree, caution as roosts in other tree-roosting members of the genus is required when interpreting the significance of this Chalinolobus (Lunney et al. 1985, Lumsden et al. 2002) observation as diurnal activity of bats is uncommonly and other microchiropteran species within Australia and observed and may be atypical behaviour. It is impossible worldwide (Lumsden et al. 2002, Kunz and Lumsden to know if the bats had been disturbed, how far they may 2003). The roost also shares some similar features to a roost used by C. picatus described by Schulz et al. (1994). have flown, if the bats were merely seeking shelter at the In both observations C. picatus used hollowed out spouts nearest suitable point, or if this was natural behavioural approximately 10m above ground level. The roost we response to the hot conditions. Nevertheless it was clear observed differed from the six C. picatus roosts recorded that the hollows observed were used as a diurnal shelter by Dominelli (2000) and the single roost recorded by for a significant number of bats on this occasion, regardless Schulz et al. (1994) in that they were all in dead trees. of the reason(s) the bats initially left their roost. References: Lumsden L, Bennett A and Silins J. 2002. Selection of roost Ayers D, Nash S and Baggett K. 1996. Threatened Species of sites by the lesser long-eared bat Nyctophilus geoffroyi and Gould’s Western New South Wales. National Parks and Wildlife Service. wattled bat Chalinolobus gouldii in south-eastern Australia. Hurstville. Journal of Zoology, London 257: 207 – 218. Dominelli S. 2000. Distribution, roost requirements and foraging Lunney D, Barker J and Priddel D. 1985. Movements and day behaviour of the greater long eared bat Nyctophilus timoriensis and roosts of the chocolate wattled bat Chalinolobus morio (Gray) the little pied bat Chalinolobus picatus in the Bookmark Biosphere (Microchiroptera: Vespertilionidae) in a logged forest. Australian Reserve. Unpublished report for the Bookmark Biosphere Trust. Mammalogy 8: 313-317. Kunz T.H., and Lumsden L. 2003 Ecology of cavity and foliage Schulz M, De Oliveira M.C., and Eyre T. 1994. Notes on roosting bats. Pp. 3-89 in Bat Ecology, edited by TH Kunz and the little pied bat Chalinolobus picatus in central Queensland. MB Fenton. University of Chicago Press, London. Queensland Naturalist 33: 35-38. Australian December 2005 Zoologist volume 33 (2) 167 Dec05.indd 167 14/02/2006, 10:08 PM