Dietary composition of birds in isolated ecosystems: a case study of Black Wood Pigeon in Republic of Korea

Abstract

We studied the feeding ecology of the Black Wood Pigeon (Columba janthina), a species endemic to the East Asian Pacific Islands, and determined the species’ dietary composition and food preferences on Ulleung Island, South Korea, through field observations. From March 2016 to February 2018, the diversity of food items consumed was low, with the 10 most common plant species (from a total of 33) accounting for over 80%. Food availability varied depending on plant abundance, but this influence was minimized because of factors such as delayed fruit ripening. Drupes were the most favored food items (60–68%) but were replaced by nuts and weed seeds during the spring and winter months. Dietary composition and food preferences were related to the abundance of food items based on their phenology, but a steady, high preference for Aphananthe aspera was observed throughout the study period. The abundance of Prunus takesimensis in June was correlated with changes in the Black Wood Pigeon population. This study is the first to assess the feeding ecology of Black Wood Pigeons using field observations and suggests that the availability of different food items affects population changes on the East Asian Pacific islands.

Keywords

• dietary composition
• feeding preference
• field observations
• fruit
• phenology
• seasonal variation