Study On Breeding Ecology Of A Reintroduced Population Of The Crested Ibis Nipponia Nippon At Dongzhai In Henan Province

The Crested Ibis(Nipponia nippon),medium sized waders,is a globally endangered bird in Ciconiiformes,Threskiornitidae,which was listed as a first grade national protected species and endangered species on the IUCN Red List.Aimed to save and restore this small population,a reintroduction program was conducted in the Dongzhai National Nature Reserve in 2007.The birds with a wild-exercising and returning nature bred successfully in the wild.The Crested Ibis reintroduction project is one of the most successful international endangered species reintroduction project.Dongzhai was the first wild-exercising and returning nature area,in addition to the Shaanxi province.However,so far,the habitat selection and breeding ecology of Crested Ibis in the Dongzhai National Nature Reserve have not been reported.To clarify the breeding status of the Crested Ibis and to provide more reference for the reintroduction of this species,the process of pairing,oviposition,incubation,brooding and nest site selection of the Crested Ibis in the wild were studied in the Dongzhai National Nature Reserve,Luoshan County,Henan Province,China,from 2014 to 2016.A total of 78 individuals(39 males,39 females)were released three times from 2013 to 2015.In these three breeding season,the focal point sampling method are used to observe and record the 10 pairs,12 nests;with a tape measure,box and needle,GPS,altimeter,and diastimeter were used to measure 16 variables of habitat characteristics;using the five point on the living area of the Crested Ibis in the fall and winter food contains investigation.The results are as follows:1.From the point of the selection of nesting tree,Crested Ibis nest-site selection has obvious diversity: as a nest tree species including Chinese red pine(Pinus massoniana),Chinese ash(Pterocarya stenoptera),loblolly pine(Pinus taeda),and princess trees(Paulownia fortunei).In 2014-2016,a total of 12 nests were recorded in the wild nests of the Crested Ibis,and the number of successful nests(at least one of the young birds managed to fly)had 10 nests,which accounted for 83.33% of the total number of breeding colonies.The total number of successful nests is 6 and some of the successful nests are 4.The proportion is 50.00% and 33.33% respectively;The total number of failed nests(no chicks flying)has two nests,and the proportion is 16.67%.2.The results of the principal component analysis(PCA)revealed that components one(1)through four(4)accounted for 79.31% of the total variance.The first principal axis showed that the nest tree height(NTH),nest height(NHE),diameter of the nest tree(DBH),distance to stream(DST)and average arbor height(AAH)were the higher loads,which mainly represented the vegetation factor and food factor.Distance to residential area(DRA),nest distance(NDI)and distance to motor vehicle path(DMV)contributed more to the second principal axis and were regarded as interference factors and nest position factors.The large loads of third principal axis were nest location(NLO)and distance to paddy field(DPF),which are known as nest position factors and food factors.In the fourth principal axis,the loads of slope position(SPO)and slope gradient(SGR)were high and are considered as topographical factors.3.A total of 78 captive-bred individuals have been released: October 2013(17 females,17 males),August 2014(13 females,13 males)and May 2015(9 females,9 males).All individuals came from the Dongzhai National Nature Reserve.The released Crested Ibis breed one nest in 2014;7 nest in 2015;4 nest in 2016.The mean diameter of the successful breeding nests tree was 39.30 ±12.54cm(n=10),and the average height of nest tree was 13.92 ± 2.01m(n=10),and the average height of the nest was 10.36 ± 1.75m(n=10).4.The Crested Ibis laid eggs from February 16 th to May 15 th.A single clutch of 2-4 eggs by each pair was laid in two-day intervals.Thirty-three eggs were laid from 2014 to 2016(two each in five nests,three each in five nests,four each in two nests).The average clutch size was 2.75±0.75(n=12).The proportion of fertilized and unfertilized eggs was 81.82% to 18.18% respectively.5.As an asynchronous hatching bird,the incubation period of the Crested Ibis was 28 to 33 days.The average hatching rate of all eggs was 78.48%.6.The rearing period varied from 39 to 46 days,and both the parents together fed the chicks.The amount of food needed and the feeding time of birds increased with the growth of nestlings.However,there was no significant difference in the frequency of feeding between parents,and they were complementary.7.A total of 23 young birds fledged: one in 2014,14 in 2015 and eight(8)in 2016.The average fledging rate was 75.00%,and the average breeding success rate was 70.14%.8.There were significant differences in the altitude of nest site,height of nest tree,height of nest and diameter of nest tree between the released and wild population.However,there was no significant difference between the released population(3.30±1.34,n=10)and the wild population(2.84±0.77,n=271)(t =1.088,P =0.305)in the average of clutch size.The average number of fledglings per successful nest was 2.3 ± 0.82(n = 10).In comparison,the wild birds did not have significant difference in the number of per successful nest(2.24 ± 0.80,n = 201).The results will help guide the recovery and expansion of the Chinese Crested Ibis and for other reintroduction programs.