Observation on Some Activities of Reproduction in Little Egrets (Egretta garzetta) at Jiyu Island in Xiamen

Data on breeding of Little egrets (Egretta garzetta) were collected in a period from March to July of 2001 at Jiyu Island in Xiamen Egret Natural Reserve.Eggs and nestlings were marked with colors for identifying the egg-laying and hatchling sequences.Ninety one percent of clutch sizes were 4 and 5,the laying period was 7.0±1.9 d,and hatching spread was 4.2±1.4 d;the incubation time was negatively correlated with the laid order of eggs;the mass was not different for the eggs laid early or late;at early stage of development (≤5 d),nestlings were not different in growth,but a significant difference appeared after then,the rate of growth and survival was the lowest for the 5th hatchling,and the second for the 4th when counting backwards.Incubation was not continuous in laying period,and became relatively continuous after that period.By this way,the parents may regulate the incubation time,and further adjust the asynchronism of incubation,resulting in a dominance hierarchy among the nestlings,which would maximize the reproductive success.