Aspects Associated with Nesting Ecology of Indian Blackbird (Turdus merula kinnisii) in Tropical Montane Cloud Forests of Horton Plains National Park of Sri Lanka

Abstract

Breeding ecology of Indian Blackbird (Turdus merula kinnisii) was studied at the tropical montane cloud forests of Horton Plains National Park, situated in the highland plateau of the central highlands, from September 2015 to August 2018 within three consecutive days per month. This sub species is endemic to montane forests of Sri Lanka. There are two breeding seasons from March to April and August to September. There was a research gap about the breeding ecology of Blackbird in Sri Lanka. The objective was to conduct a detailed study about breeding ecology. Three habitats were selected within HPNP as cloud forest, cloud forest die-back and grassland habitat. Nests were located by following individuals and searching the vegetation. The location of the nests were marked by a GPS (Garmin eTrex 10). Tree species, nest height, diameter at breast height (DBH) was measured after the birds leaving the nest. Nest concealment, distance from the nest tree to the adjacent tree, nearest road or walking path and water source, was measured. Disturbances for the nests were observed and recorded. Nests accessible from the ground were only taken for inner nest parameters. In this study 30 nests were observed. Most of the nests were located at cloud forest habitat (n=26).They preferred seven plant species to construct their nests. Neolitsea fuscata was their major nesting plant. The nest height was 3.87±1.42 m and the nesting tree height was 7.01±1.71 m. The nests were located in the middle of the trees (relative height=0.56±0.18). Nest concealment was 14.33±4.30%. They highly preferred medium sized trees which were situated at shady habitats near water sources. The nest was a densely built cup with a volume of 936.4±157.5 cm3. Sometimes there were dummy nests around the original nest to protect from predator attacks. They spent 7 to 9 days to complete the nest. The incubation ranged from 16 to 18 days. Nestling period ranged from 13 to 15 days. The adults considered sole care of the young until it become an adult. Nesting success was 73%. Corvus splendens was recorded as the major predator. Present study reveals that cloud forest habitat as the most suitable habitat to construct the nests of Blackbird. Hence, the protection of cloud forest habitat is the assurance of their future generations.
Keywords: Indian blackbird (Turdus merula kinnisii), Endemic subspecies, Tropical montane cloud forests, Horton Plains National Park, Breeding ecology