Abstract:
Oliyagankele forest reserve is a lowland wet zone forest, situated between
Akuressa and Kamburupitiya, which covers an area of 482.9 ha. Its fauna has not
been thoroughly investigated. This study was carried out to enhance the taxonomic
knowledge of its avifauna. The objectives of the study were to find out the bird
distribution, abundance and the evenness of avifauna in selected habitats. The
survey was conducted during a period of five months (from April to August) in
2004. The study was based on the point scan line transect technique. Six
different habitats were studied and a checklist of recorded bird species was
prepared. Results indicated that the avifauna of Oliyagankele represented 10
orders, 24 families 35 genera, 42 species and 13 sub species including
approximately 1/5 of endemic birds of Sri Lanka. There was no significant
difference in the vertical vegetation distribution pattern among six selected
habitats. However, there was a significant difference in the Index of Horizontal
Heterogeneity (IHH) between selected habitats. Analysis of total bird count made
during mornings and evenings as well as rainy days and sunny days revealed that
there were no significant differences in the species diversity and evenness.
However, there was a significant positive correlation between the species diversity
in the mornings and evenings. There were also significant differences in the
abundance of bird (absolute number recorded) in the selected habitats during the
mornings and the evenings and as well as during rainy days and sunny days.
Similarity of all bird species was highest between the site 1 and site 3; lowest
between site 2 and site 4. The IHH and Index of Vertical Heterogeneity (IVH) for
selected habitats were not shown to be significantly correlated with overall species
diversity, abundance and evenness. However there was a significant difference
between the distribution of bird community in different vegetation strata and
among selected habitats.
