ORIGINAL ARTICLE Wildl. Biol. Pract., 2014 December 10(2): 102-110 doi:10.2461/wbp.2014.10.13 Copyright © 2014 V.K. Koli & C. Bhatnagar. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distri- bution, and reproduction in any medium, provided the original work is properly cited. Published by: Portuguese Wildlife Society. Calling Activity of Indian Giant Flying Squirrel (Petaurista philippensis Elliot, 1839) in the Tropical Deciduous Forests, India V. K. Koli 1,* & C. Bhatnagar 1 1 Wildlife Research Laboratory, Department of Zoology, University College of Science, Mohanlal Sukhadia University, Udaipur (Rajasthan), 313 001, India. * Corresponding author email: vijaykoli87@yahoo.in. Keywords Calling bout; GBH; Petaurista philippensis; Perch height. Abstract The calling behaviour of Petaurista philippensis was studied from March 2009 to February 2010, in the tropical deciduous forests of the Sitamata Wildlife Sanctuary, Rajasthan, India. Surveys were conducted from the dusk or 1900 hr to 0600 hr. A total of 268 call bouts were recorded. Call frequency was highest in March 2009. The most vocal periods were midnight and early night, just before entering into the nest cavities. Annual, seasonal and daily call frequencies were insigniicant (P > 0.05) between male and female. 5-10 min call bout category contained highest account (40%). Calling was mostly performed in the mid canopy area of the trees. Perch height was found positively related to tree height. Introduction Detailed information on the ecology of the lying squirrels is scarce, due perhaps to their low population density, arboreal, nocturnal and cryptic or elusive habits. According to Corbet and Hill [1] a total of 44 species of lying squirrels belong to 14 genera present worldwide. Except three species (Glaucomys volans, G. sabrinus and Pteromys volans) all other (Petaurista, Eupetaurus cinereus, Hylopetes, Eoglaucomys, Petinomys, Trogopterus, Belomys, Pteromyscus, Petaurillus, Lomys, Biswamoyopterus and Aeretes) species are found in Asia [2]. Petaurista philippensis is dominant among all species and widely distributed in the tropical and sub-tropical zones of south-east Asia [3-5]. It is a typical inhabitant of the forests in lowlands and mountains up to 4000 m [6]. A total of 13 lying squirrel species found in India, wherein two are recently identiied in last decade namely Petaurista nigra [7] and P. mishmiensis [8]. P. philippensis has a broader distribution among them and restricted to the northeast region of Himalaya (Tropical moist deciduous forest) and the Western Ghats (Tropical wet evergreen forest) [9-13]. A few patches of occurrence have been reported from the southern peninsula, which fall under moist temperate forest [12], whereas southern Rajasthan (Tropical deciduous forest) is an isolated distributional patch in tropical deciduous forests of western India [5, 14, 15]. P. philippensis roosts in cavity nests [5] and feeds