Effects of Environmental Stress on the Parental Behavior in Crested Ibis (Nipponia nippon)

Abstract

When maintained in captivity in 'intensive aviaries' that offered suboptimal and unnatural living conditions, parent Crested Ibis successfully incubated their eggs but subsequently killed the chicks and discarded them at the point of hatching. In order to investigate this aberrant behavior, new 'semi-natural' breeding cages were established in natural woodland habitat, and the parental behaviors of five breeding pairs from F1 and F2 generations were examined using video recordings. Over the three-year study period, 13 chicks hatched and were successfully raised by the parents in the semi-natural cages, whereas no parental care was provided to those chicks that hatched in the intensive aviaries, and all perished. This experimental evidence revealed that their killing of the chicks might be a consequence of environmental stress caused by their inability to adapt to the artificial environment of an unnatural enclosure. We concluded that the environmental conditions under which they are maintained is a crucial factor for the behavioral adaptation and captive breeding success of this endangered species.