Territoriality of Copsychus malabaricus in Western Part of the Mihintale Sanctuary, Sri Lanka

Abstract

The White-rumped Shama (Copsychus malabaricus) (WRS) is a small passerine bird whichhas a melodious song and solitary behaviour that holds a territory all year round. Research onterritorial behaviour of WRS is scare in Sri Lanka. Present study was carried out from May toAugust in 2013 at western border of the Mihintale sanctuary to investigate the territorialbehaviour of WRS. The behavioural studies were done by using the focal sampling method.A dummy of WRS and play back calls were used to check the aggressive behaviour andterritory variations of the bird. Territorial mapping was done using standard methoddescribed by Bibby et al (1993). Breeding success was measured by number of eggs in eachnest and number of chicks emerged from relevant nest. The frequently used trees for nestbuilding were measured by frequency of visiting time of each tree species. Individuals ofWRS were marked with coloured plastic rings prior to the study. Three territories wereselected from fragmented and non-fragmented forest patches to continue the study. Duringthe non-breeding period size of territory is approximately 26,255.6 m2 while during thebreeding period their territory size varies to 20,777.51 m2 – 33,296.03 m2. The size of theterritory depends on the degree of habitat disturbances. The results revealed that thesuccessful breeding was observed in non-fragmented forest patch than the fragmented forestpatch. Calling (43%) and moving (43%) behaviours were high in male and femalerespectively during the non-breeding period. During the breeding period lifting tail wasprominent in male while preening was prominent in female. Every 13 seconds male producedcalls both breeding and non-breeding periods. During the site selecting period both have highpercentage (male -50% and female -54%) of moving while during the nest guarding period,male showed high tail lifting and calling behaviours. The perching height varies with the siteselecting behaviour. Average perching height of male and female ranging from 2.348 m(±1.2) to 3.41 m (±1.87) and 1.25 m (±0.75) to 2.63 m (±0.89) respectively. Perching heightis significantly different (p< 0.05) during the breeding and non-breeding periods. Drypetessepiara and Pterospermum canescens were frequently used trees for the nest building. Theyselected 49-150cm height from the ground level for nest construction and the nest length is9.85 cm, 7.7 cm width and thickness is 2.7 cm. Parts of Ficus aerial roots, dried leaves, sticksand grasses used as for nest building materials. Average clutch size was 2±1 and length ofegg was 2.14 cm-2.35 cm and width was 1.18-1.6 cm (ρ=-0.990).