Abstract
The breeding ecology of the Coot Fulica atra was studied on Lake Teganuma, Chiba, central Japan, from April to October 1990. Nests were built in 2-7 days, and used for copulation and egg laying. The egg laying period ranged from early April to mid-July, peaking in May. One egg was laid per day and clutch size varied from 3-8 eggs, with an average of 5.2. Eggs weighed between 30 and 40g, averaging 34.9g. The mean size of 120 eggs from 23 nests was 52.0×35.5mm. Most nests (86%) were placed in Typha angustata, and the other nests (14%) in Zizania latifolia. Both males and females incubated eggs. The interval of incubation was 51 minutes on average. The incubation period ranged between 21 and 25 days. The second nest was constructed once the eggs had hatched. Of a total of 126 eggs laid in this study area, 32% hatched, with only 12% of the eggs remaining after two weeks.
