山西省代县小鸊鷉繁殖生物学的研究

RESEARCH ON THE BREEDING BIOLOGY OF LITTLE GREBE IN DAIXIAN COUNTY, SHANXI PROVINCE

１９８５—１９９４年的３—１１月，在山西省代县对小鸊鷉的繁殖生物学进行了研究。该鸟在山西省为夏候鸟，每年最早３月６日迁来，最晚１１月２４日迁离，居留期为２５５天左右。种群密度在繁殖前的４月为１．３７，繁殖后的９月为１．９５（只／ｈａ）。产卵始期为５月２７日，日产１枚，窝卵数５—８枚，产出第二枚卵时开始孵卵。观察到最早孵卵期为５月２８日，孵卵期２０－２２ｄ。雏鸟出壳先后顺序与产卵先后顺序相一致，孵化率为９５．４５％，雏鸟为早成鸟。

From March to November during 1985-1994,we investigated the breeding status.of Little Grebes'in Daixian County,shanxi Province.The birds are summed residents in shanxi Province,they remain on the breeding grounds for 252-258 days(from March 6-14 to November 18-24).Thepopulation density was 1.37 per ha.In April before reproduction and 1.95/per ha.In September afterreproduction.The earliest egg-laying was dated on May 27,an egg was laid each day after then,theclutch sizes were 5-8.The hatching started after the birds laid their,incubation period lasted for 20-22 days.The sequence that chickens pipped out of eggshell that of egg-laying.The incubation rate was95.45%