Acta Zoologica Cracoviensia, 40(2) 1997

Issue:

VOL 40(2) 1997

Keywords:

Nycticorax nycticorax, nesting, eggs, nestlings, breeding success

Download PDF

Share this article:

Breeding ecology of the Black-crowned Night Heron in Korea

• Jae-Pyoung YU
• Kyu-Hwang HAHM

Abstract:

Breeding ecology of Nycticorax nycticorax was studied in 1993 in the heronry situated near the Junam reservoir in Kyungnam Prov., Korea. 67 nests were built in Pinus densiflora and Robinia pseudoacacia trees; mean height of trees was 7.81 m and mean height of the nest sites above the ground was 7.29 m. The number of nests built in a given tree increased with the increasing breast height diameter of its trunk. The average sizes of nests were as follows: outer diameter 46.5 cm, inner diameter 22.3 cm, height 17.8 cm, depth 4.4 cm. One nest was made of 169-379 sticks. Full clutch consisted of 3-5 eggs, laid at 2 days’ intervals. Elliptical eggs were spotless, pale bluish-green; their mean size was 50.8x35.0 mm and mean weight after laying 34.6 g. The incubation started with the first egg and lasted 22.4 days. The chicks’ food consisted of fish (72% of items), insects (16%) and amphibians (12%). Hatching success: 90.91%, fledgling success: 53.33%.