Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence under 20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (under 10,000 mature individuals with a continuing decline estimated to be over 10% in ten years or three generations, or with a specified population structure). The population trend appears to be fluctuating, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (over 30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size is estimated at 37,000-1,113,999 individuals (Wetlands International 2023), which equates to 24,700-743,000 mature individuals. The overall population trend is considered to be fluctuating over three generations (25.98 years) (Wetlands International 2023).
Trend justification
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Nycticorax caledonicus occurs in the Philippines, Indonesia, Australia, Papua New Guinea, the Solomon Islands, Palau, New Caledonia (to France) and the Caroline Islands, Federated States of Micronesia. The subspecies crassirostris, which was endemic to Japan's Bonin Islands, has been extinct since the late 1800s (del Hoyo et al. 1992).
Text account compilers
Rutherford, C.A.
Recommended citation
BirdLife International (2024) Species factsheet: Nankeen Night Heron Nycticorax caledonicus. Downloaded from
https://datazone.birdlife.org/species/factsheet/nankeen-night-heron-nycticorax-caledonicus on 24/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 24/11/2024.