Impact of Anthropogenic Land Alterations on Bird Diversity, Abundance and Feeding Guild in Nilgiri District

Abstract

In this study, avian data was collected using Line transect method in anthropogenically altered landscapes of Nilgiris district. A total of 108 species of birds were observed in the eight sampling locations. The total number of birds recorded stood at 14212 and the total number of observations at 8771.  The number of resident bird species stood at 95.  The species count for winter migrants and passage visitor stood at 12 and 1 respectively. Number of Endemic species observed was 8.  Under the category of well wooded area: tea estate in Kunjapanai and Catherine with diversified shade trees; and SIMS park (botanical garden) were chosen.  Under the category of tea monoculture area (under monotypic shade tree of Grevillea robusta) locations of Mullur, Dolphin Nose and Attadi tea estate were included. Residential area of Brookland (Coonoor taluk) and Commercial area of Coonoor town were chosen under the urban area category.  Avian data was analysed both under both landscape level and at patch level. The objective of this study is to ascertain the status of bird richness and abundance in these varying landscapes. The number of species recorded in landscape categories of well-wooded area, tea monoculture area and urban area stood at 103, 60 and 34 species respectively. At patch level, Kunjapani, Catherine and SIMS park had higher bird richness and abundance when compared with the three areas of tea planation under monotypic shade of Grevillea robusta. The Coonoor town area had the lowest species count but had the highest bird abundance.  Attadi tea estate (tea monoculture area) had the lowest bird abundance.  Tea gardens under the monotypic shade tree of Silver Oak support few bird species, and with low abundance. Conversion of these areas into urban areas will only serve to increase the abundance of a handful of omnivores.