Nest Architecture and Material Characteristics of Wild-Breeding Reintroduced Crested Ibis (Nipponia Nippon) in South Korea: Implications for Conservation and Pre-Release Conditioning

Successful reintroduction of endangered birds depends not only on post-release survival but also on the recovery of natural reproductive behaviors such as nest construction. However, information on nest architecture in reintroduced populations remains limited. We examined the architecture and material composition of two nests built by wild-breeding, reintroduced Crested Ibises (Nipponia nippon) in South Korea. The nests, built by different breeding pairs in consecutive years within the same territory, were divided into Bottom, Middle, and Upper layers, and materials were classified as woody, herbaceous, crop, or other. Material length, dry mass, and diameter were measured, whereas fine lining materials were quantified by bulk dry mass. Woody materials accounted for 80.7–85.3% of total dry mass and were concentrated in the Bottom and Middle layers, whereas herbaceous materials occurred mainly in the Upper layer. Material size and mass decreased progressively from the Bottom to the Upper layer, indicating clear vertical differentiation in nest structure. Because only two nests were available, the results are presented as descriptive baseline information. These findings provide reference information that may assist material provisioning and enclosure design for pre-release conditioning of reintroduced populations.