Abstract: Thirtyfour captive Crested Ibises (Nipponia nippon) were acclimatized in a large cage prior to release to the wild at Dongzhai National Nature Reserve of Henan Province from March to October, 2013. The captive Crested Ibises gained flying ability similar to wild ones within a week, and shifted nocturnal roost from ground to artificial roost bars, and finally to trees within 10 days. The ibises acclimatized a variety of foraging habitats in two months, stepwise from dry land to marsh, and from shallow water to deep water. The acclimated Crested Ibises had defense instinct against natural raptors, with the vigilance distance and flushing distance as 300 and 50 m respectively; but the ibises showed little vigilance against their care keepers. In the acclimating cage, 66.7% of the breeding pairs divorced. The longer a pair bred together, the more stable the pair bonded. Chick rearing experience had no significant influence on the reproductive success, and overcrowded nesting and frequent disturbance were the main factors resulting in the breeding failure of the ibises in the acclimating cage. The result indicated that captive Crested Ibises could be released to the wild after acclimation for 2-3 months. Improving acclimating management, such as roost bar construction and food supplementation, will enhance the acclimating efficiency. Post-release monitoring and evaluation on adaptability, survival rate and reproductive success are necessary to assess the acclimation efficiency.

Key words: landscape pattern, ecological risk, spatial auto-correlation., geostatistical feature, temporal and spatial change