| The Crested Ibis Nipponia nippon was endangered species in Ciconiiformes, Threskiornitidae, which was listed as a first grade national protected species and endangered species on the IUCN Red List. Only7individuals worldwide of wild population were rediscovered in Yangxian. Shaanxi Province in1981. Since then great attention was attracted by the Chinese government and related research institute. in-situ, ex-situ conservation and reintroduction has been taken in order to restore and establish a new colonizing population which can make it sustainably and steadily for reproducing during the past30years and received a great success. Currently,8captive populations were successfully established around the world. By the end of2008years, the wild population has increased from7individuals to approximately800birds and with more than1,000captive-bred individuals.Reintroduction was one of the effective ways to save the endangered species. During2003to2005, Ningshan County of Shaanxi province was confirmed to be the first reintroduced site after a pre-investigation to compare with the original habitat of wild population in Yangxian County. From May2007to October2011,56captive-bred individuals, including26females and30males, were released to the Ningshan County subsequently in four times. So far,10breeding pairs has been formed and33nestlings fledged successfully by the end of2011amongst the reintroduced population. The reintroduction program of the Crested Ibis was considered to be a successful story of the worldwide reintroduction program.The paper aimed to describe the past and current distribution, extinguishing process and reasons, the status of research and conservation of the Crested Ibis. The breeding ecology, especially reproductive success was highlighted and the factors concerned with the reproductive success in each stage of a breeding season were summarized. Comparative analysis of breeding biology between the reintroduced population and wild population was summarized, as well as the management during post-release period.A single clutch of1-5eggs (usually four) was laid between2th of March and8th of May from2008to2012. The average clutch size did not vary significantly among years (F=0.259. P=0.854. df=3). A total of21clutches (including66eggs) was laid and average clutch size was3.14±1.06(n=21) among4years. There was a slight fluctuation in clutch size which varied highly significantly (t=13.557,P=0.000.df=20) during the21clutches.Of the21clutches, the proportion of successful nests (at least one nestling fledged successfully) was80.9%(17clutches). Accordingly, the proportion of completely and partially successful nests was23.8%(5clutches) and57.1%(12clutches) respectively. The number of unsuccessful nests which produced no nestling was4(19.0%).The average hatching rate, which did not vary significantly among years (F=0.549, P=0.656>0.05, df=3) was69.92%(0-100%). in accordance with the fluctuation of reproducing success during the4years. The egg losses were contributed to infertile or addled eggs and predation. In total,20eggs were lost during4breeding seasons.The average fledging rate which differed significantly among clutches (t=8.196, P=0.000<0.01, df=20) was52.86%(0-100%). However, there has no significant difference during the4years (F=0.724, P=0.552, df=3). The average breeding success of the overall breeding pairs was52.86%(0-100%) and varied highly significantly among the clutches (t=6.785,P=0.000<0.01, df=20). Starvation in early nestling stage and predation were the main reasons for nestling’s death. A total of12nestlings died during4breeding seasons.The average clutch size, incubation number, fledging number and breeding success did not decrease significantly between late March and middle April (t=1.635, P=0.126; t=0.821, P=0.426:t=1.038, P=0.318;t=0.163, P=0.873). The average clutch size in the late April significantly decreased (t=2.846, P=0.016). The factor such as food richness exert an apparent effect on the fledging success (t=3.261. P=0.008).The minimum age at first reproduction of the reintroduced population was only11months. The average age of these individuals at first breeding was4.05±2.93(n=17) years. First breeding by males was not significantly later than females (males4.88±3.09years n=8:females3.32±2.75years n=9,t=1.906, P=0.291). The mean clutch size, incubation number and fledging number of2-3years-old individuals were not significantly lower than that of4-9years-old birds (t=1.632. P=0.112; t=-0.817. P=0.420;t=-1.317, P=0.197). The mean clutch size, incubation number, fledging number and reproducing success varied not significantly among three age groups (F=1.355,P=0.270;F=0.312,P=0.734;F=0.940,P=0.399; F=0.198, P=0.821, df=2).The mean clutch size, incubation number, fledging number did not sinnificantly correlate with altitudes of nest sites(Pearson r=0.324, P=0.153; r=0.240, P=0.295: r=0.212, P=0.357, n=21).The breeding success has no significant difference amongst the three altitudinal zones(F=0.767.P=0.479, df2). |
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