Artificial nests as a tool to maintain nest success rate of Black-necked Cranes (Grus nigricollis) at Qinghai Lake, China

Abstract

The Black-necked Crane (Grus nigricol-lis) only breeds in high-altitude wetlands of the Tibetan Plateau. An important breeding area for this species, Qinghai Lake, has recently undergone large water level changes both inter- and intra-annually. Continually rising water between years and rapid rise of water levels during Black-necked Cranes' hatching period led to inundation of eggs. Hatching success among a study population of 13 nests at Qinghai Lake had a mean of 30.77% during 2009–2014. To examine (1) how readily Black-necked Cranes might adapt to artificial nests, and (2) whether artificial nests can improve their breeding performance, we built artificial nests for Black-necked Cranes at Qinghai Lake during 2015–2017. Results showed that Black-necked Cranes adapted well to artificial nests with 16 pairs hatching young in the structures out of 27 attempts, and the occupation rate exceeded 50% in 3 years. Furthermore, cranes using artificial nests had high hatching success rates of 77.78%, 100%, and 72.73%, respectively, and breeding success rate was 11.11–22.22% less than hatching success rate each year. Compared with Black-necked Cranes using natural nests in the study area during 2009–2014, nesting success rate of Black-necked Cranes that used artificial nests during 2015–2017 improved significantly. Therefore, we propose that artificial nests can be used to maintain Black-necked Cranes' nest success rate at Qinghai Lake; our study contributes to the protection of this species in the future.