Bird diversity on the campus of the Indian Institute of Science-An evaluation of two methods of estimation

Abstract

Two methods, namely, short strip transect count (SSTC) and point count (PC), were evaluated to select a robust method of estimating bird diversity on the campus of the Indian Institute of Science, a man-made ecosystem. For bird species/h (PC= 6.7, SSTC = 3.0) and the number of birds/km2/h (PC= 184.7, SSTC = 40.3), the PC method encountered more species and individuals in relatively shorter time. The mean number of sightings and species per minute (sightings: PC= 1.31, SE 0.08, SSTC = 0.94 SE 0.07, species: PC= 1.09, SE 0.06 and SSTC = 0.67, SE 0.03) were also more in the PC method and the differences are very significant (sightings: .:: = 3.09, p < .001 and for species, z = 5.48, p < .001). Species accumulation curve, richness, diversity (H' = 1.98 (PC) and 1.75 (SSTC)), and evenness (E) (0.610 for PC, and 0.50 for SSTC) also favoured the PC method. These results indicate that the PC is an appropriate method for estimating bird diversity. The paper also discusses the possible ecological reasons for PC being a robust method.