欧夜鹰的繁殖生态与移巢行为

Breeding Ecology and Nest Moving Behavior of Eurasian Nightjar(Caprimulgus europaeus) in Xinjiang, China

2008年6至8月及2018年6月和7月,采用实地观察、测量和红外相机监测方法对新疆乌鲁木齐郊外头屯河流域欧夜鹰(Caprimulgus europaeus)的栖息环境、巢间距、窝卵数、孵卵、育雏、幼鸟生长及移巢行为进行了调查和分析。利用红外相机监测3个巢,监测时间分别为15d、23d和11d,共拍摄照片8462张,视频4152个片段,约40h,经过筛选得到有效照片6807张。结果表明,欧夜鹰的巢均置于河道中央的河心岛及乱石滩沙地上,周围植被稀疏。两巢间距最近为69m,巢密度3~7个/km^2。每窝产卵2枚(n=7),卵长径为(30.53±0.88)mm,卵短径为(21.39±0.85)mm,卵体积为(7.13±0.50)cm3,卵重为(7.27±0.38)g(n=5)。孵卵期为15或16 d,孵卵期成鸟离巢觅食呈双峰型,分别在天黑后的20:00~21:00时和黎明前的03:00~04:00时。育雏期为16~18 d,育雏期和孵卵期成鸟活动强度存在明显的差异,成鸟喂食幼鸟亦呈双峰型,分别在夜里的20:30~22:30时和黎明前的02:30~04:30时。成鸟的行为谱可分为9类46种,幼鸟的行为谱可分为6类32种。雏鸟的体重、体长、翅长生长发育遵循Logistic方程规律,呈曲线变化,尾长、跗跖长和嘴峰长则遵循线性生长规律。欧夜鹰的移巢行为十分独特:一是为了躲避日晒,以避免幼鸟被阳光灼伤;二是避开干扰(天敌、牧群、洪水及人类活动等)。

During May to August in 2008 and 2018,we studied the basic breeding ecology of the Eurasian Nightjar in the basin of the Toutun River near Urumqi through field investigation,measurement and infrared cameras monitoring,and found the nest moving behavior of the bird.Altogether we found 7 nests of the nightjars,which were located on the sloping sands of the riverbanks with sparse vegetation.The nearest distance between nests is 69 m,and a density is 3﹣7 nests per square kilometer.Clutch size is 2 eggs (n=7),with egg mass of 7.27±0.38 g,egg length and width of 30.53±0.88 mm and 21.39±0.85 mm and egg volume of 7.13±0.50 cm^3 (n=5,Table 1).Three nests were monitored by infrared cameras for15 days,23 days and 11 days respectively,with a total of 8 462 photos,4 152 video clips about 40 hours,and 6 807 valid photos acquired.We systematically investigated and analyzed incubation,nestling feeding,nestling growth of the nightjars.During the incubation period which lasted for about 15﹣16 days,the adults were leaving nests for feeding in a bimodal pattern,with peaks occurred at 20:00 to 21:00 and 03:00 to 04:00 respectively (Fig.1).The nesting period lasted about 16﹣18 days.There was a significant difference in activity intensity between nestling feeding and incubation period.The adults fed young birds also in bimodal way,however,the peaks were occurred from 20:30 to 22:30 at night and before dawn at 02:30 to 04:30 (Fig.2).The breeding behavioral spectrums were classified into 9 categories including 46 behaviors for parents,and 6 categories including 32 behaviors for nestlings.Their growth changes in body length,weight and wing followed a logistic growth curve,however,for the tail length,tarsus and rostra it followed a linear increase (Fig.3,Table 2 and Table 3).We found the unique nest moving behavior of the Eurasian Nightjar with the moving distances and details shown in Table 4,for the reasons of moving the nests,we suggest that one was to prevent the young birds from being burned by the sun,and the others were to avoid disturbances (natural enemies,herds,floods,human activities,etc.).