The mixed breeding site of Great Cormorant (Phalacrocorax carbo) and birds in the family Ardeidae in inland of South Korea

Abstract

This study investigated the mixed breeding site of Great Cormorant (Phalacrocorax carbo) and birds in the family Ardeidae in the forest near the reservoir located in Goesan-gun, chungcheongnam-do from May to August, 2016. In order to reveal the use of breeding site and the habitat environment of Great Cormorant and Ardeidae, we measured nest tree and nest height, and observed the number of individuals remaining in nests. Great Cormorant and Grey Heron preferred False acasia (Robinia pseudoacacia), Sawtooth oak (Quercus acutissima) and Great Egret (Ardea alba modesta), Intermediate Egret (Egretta intermedia) preferred False acasia as nest tree in A site. The height of the nest of Great Cormorant was 10.9±2.7m, the height of the Grey Heron nest was 10.5±1.83m, and the height of the Ardeidae nest was 7.8±1.3m. Great Cormorant, Grey Heron and Ardeidae were preferred to False acasia, Oriental white oak (Quercus aliena) at B site in the study area. The height of the nest of Great Cormorant was 13.1±1.7m, the height of Grey Heron nest was 10.1 ± 1.9m and the height of the nest of Ardeidae was 11.3±2.3m. The average individual of adults and juveniles of Great Cormorant in the mixed breeding species decreased during the noon and rapidly increased at the sunset. During the study period, the average individual decreased during the noon, and the individual increased rapidly at sunset, it indicates that all the individuals came in after feeding. Cattle Egret (Bubulcus ibis) used the study area as a sleeping place since mid June while no other birds used as roosting sites for 1 - 3 weeks. After that, the site has been used for 11 weeks.