Justification of Red List Category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <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 trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). 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 (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The population trend is difficult to determine because of uncertainty over the extent of threats to the species.
This species is found exclusively on Australia and New Zealand, wintering along the whole coast and inland in both countries. It breeding exclusively on the north island of New Zealand, with scattering breeding site, mostly coastal, in Australia (del Hoyo et al. 1992).
This species is mostly marine, especially is western Australia, but occupies a variety of water bodies both offshore, on the coast and inland. Fish comprise roughly 90% of the body and weight of its diet, but it will also feed on crustaceans, including prawns, shrimps and crabs, and a few molluscs and cephalopods. It feeds exclusively by pursuit-diving and often forms feeding flocks at sea. Its breeding season varies considerably with region and year depending on local conditions, generally forming colonies in a variety of habitats. Adults are basically sedentary, with juveniles performing fairly extensive dispersal (del Hoyo et al. 1992)
Text account compilers
Ekstrom, J., Butchart, S., Calvert, R.
BirdLife International (2019) Species factsheet: Phalacrocorax varius. Downloaded from http://www.birdlife.org on 10/12/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 10/12/2019.