Incubation strategies of the Black-necked Crane (Grus nigricollis) in relation to ambient temperature and time of day

Avian Research

Yongjun Se¹  Xilite Dabu¹  Yila Suo¹  Bei An²  Lixun Zhang³  Meilin Shu³  Changming Zhao³  Xiaojun Yang⁴ 

[1] National Nature Reserve of Yanchiwan;School of Basic Medical Sciences, Lanzhou University;School of Life Sciences, Lanzhou University;State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences;

关键词: Time of day;    Ambient temperature;    Egg-turning frequency;    On-bout duration;    Nest attendance;    Recess frequency;   

DOI  :  10.1186/s40657-017-0076-3

来源: DOAJ

【 摘 要 】

Abstract Background The behavior of cranes reflects many of their survival strategies, but little has been known of the incubation strategies of cranes, in which both parents share incubation duties, in response to cold temperatures in alpine environments. The lack of information may restrict the effective conservation of the threatened Black-necked Crane (Grus nigricollis), a biparental bird nesting in high elevation wetlands. Methods We directly observed and used infrared video cameras from 2014 to 2015 to study the incubation behavior and quantitatively measured the frequency and details of egg turning behavior in the Black-necked Crane at the Yanchiwan National Nature Reserve in western Gansu Province, China. Results At lower ambient temperatures in the morning, crane parents spent more time on the nest with less recess frequency and prolonged on-bout duration, while at higher temperatures around noon, the parents had more frequent recesses from incubation and shorter periods between nest exchanges. They adjusted the amount of time incubating by varying the recess frequency and the length of on-bout duration. Mean nest attendance and egg turning frequency of females were significantly higher than those of the males. The nest attendance and on-bout duration of females showed a significantly negative relationship with those of males. The two parents responded differently to the change of temperature. Females spent more time on the nest at lower morning temperatures, while males increased their time on the nest at higher temperatures after noon. Higher incubation recess frequency and egg turning frequency were observed at noon, probably because parents spent more time foraging, taking advantage of the lower egg cooling rate. Conclusion Both Black-necked Crane parents in the alpine environment adjusted their behavior in response to the thermal requirements of eggs and the weather conditions experienced. Our findings demonstrate that parents of this species incubated in different but complementary ways and efficiently enhanced egg care in a dynamic environment, so as to maximize benefits from the warm portion of the day and the intense solar radiation while minimizing the cost of rewarming eggs and the risks of cooling eggs.

【 授权许可】

Unknown