Experimental reintroduction revealed novel reproductive variation in Crested Ibis Nipponia nippon
The Crested Ibis Nipponia Nippon formerly occurred throughout East Asia, but since 1981 its unique population has been confined to a narrow area in Central China. During 2004-2005, 23 Crested Ibises were experimentally reintroduced to an isolated basin in Qinling Mountains, where they and their offspring exhibited variation in reproduction never observed in wild population. Crested Ibis has been considered to be a monogamous species, and breeding pair is solitary and territorial in breeding season. However, 3.4% of breeding females exhibited polyandry and 43.1% of nests were observed in colony in the reintroduced population during 2006-2014. The mating system flexibility is likely related to male-biased sex ratio in the small isolated reintroduced population, due to greater dispersal capacity by female. The colonial nesting is attributed to the availability of large nest trees and abundant food supply. First nest failure in reintroduced population occurred much earlier than that in wild, which resulted in significantly higher probability of renesting. The phenotypic plasticity in Crested Ibis may play important role in the restoration of this critical endangered species under a changing environment, and future reintroductions provide opportunity to further understand the degree and cost of adaptive phenotypic plasticity in Crested Ibis.