BirdLife Species factsheet for Northern Cassowary: http://datazone.birdlife.org/species/factsheet/northern-cassowary-casuarius-unappendiculatus
Northern Cassoway, Casuarius unappendiculatus, is found only in the lowlands of northern New Guinea, in Papua New Guinea and Indonesia, inhabiting forest and swamps (Coates 1985. Beehler et al. 1986). Its habitat is slowly declining with forest loss in north coastal Papua New Guinea (West Sepik, East Sepik and Madang provinces) at 1.4% and habitat degradation at 3.5% between 2002 and 2014 (Bryan and Shearman 2015). The rates of habitat loss and degradation for Indonesian New Guinea have not quantified but may be similar (G. Dutson in litt. 2016). The species is also threatened by hunting, with cassowaries being a major source of food for subsistence communities, as well as being culturally important. Its use in traditional culture includes use as gifts in pay-back ceremonies and use of the feathers and bones as decoration and bones as tools (Coates 1985, Beehler et al. 1986, K. D. Bishop in litt. 1999). Hunting and trade is unsustainable in some areas with some sites having lost the species as the species is traded at a sub-national level to supply markets in more densely populated areas (Johnson et al. 2004).
It is currently listed as Vulnerable under criterion C2a(i) on the basis of an estimated small and declining population (see BirdLife International 2017), but more recent information suggests that the species may warrant downlisting. A recent study found that this species occurred at 14 (9-21) individuals per km2 in primary forest, 10 (5-17) individuals in >30 year old secondary forest, 4 (2-8.5) individuals per km2 in recently logged forest and 1.4 (0.4-5.6) individuals per km2 in forest gardens (Pangau-Adam et al. 2015). Using a mean density estimate of 7.4 (5.7-9.6) individuals per km2 and assuming only a proportion of its range is occupied the population size likely falls in the range 10,000-19,999 mature individuals (G. Dutson in litt. 2016), rather than the 2,500-9,999 mature individuals range currently used. Given the threats this species faces, the population is suspected to be declining, but an accurate rate has not been clearly quantified. The rate of decline is suspected to be <10% over 3 generations (G. Dutson in litt. 2016), but as the level of confidence in this value is low, because it is ‘suspected’ rather than directly estimated or observed, this rate of decline cannot be used to assess the species against criterion C1.
Based on current knowledge, the species may not meet the threshold for Vulnerable under any other criteria either. The suspected rate of decline is too low for the species to approach the threshold for Vulnerable under criterion A, and its range size is too large to approach the threshold for Vulnerable under criterion B. The population structure also means that the species is unlikely to approach the threshold for Vulnerable under criterion C2, while the population size estimate is far greater than required to meet the threshold for Vulnerable under criterion D. To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species, and so cannot be assessed against criterion E. Therefore, it is deemed to not approach the threshold for Vulnerable under any criterion, and would warrant listing as Least Concern. However, we welcome any comments and further information regarding this proposed downlisting, particularly regarding population trends, to see whether the species may instead warrant listing as Near Threatened.
Beehler, B. 1985. Conservation of New Guinea rainforest birds. In: Diamond, A.W.; Lovejoy, T.E. (ed.), Conservation of tropical forest birds, pp. 233-247. International Council for Bird Preservation, Cambridge, U.K.
BirdLife International. 2017. Species factsheet: Casuarius unappendiculatus. Downloaded from http://www.birdlife.org on 29/03/2017.
Coates, B. J. 1985. The birds of Papua New Guinea, 1: non-passerines. Dove, Alderley, Australia.
Johnson, A.; Bino, R.; Igag, P. 2004. A preliminary evaluation of the sustainability of cassowary (Aves: Casuariidae) capture and trade in Papua New Guinea. Animal Conservation 7(2): 129-137.
Pangau-Adam, M. Z.; Noske, R. 2009. Wildlife hunting and bird trade in northern Papua. In: S. Tidemann, A. Gosler and R. Gosford (eds), Ethno-ornithology: Global Studies in Indigenous Ornithology, Culture, Society and Conservation, pp. 73-85. EarthScan, London.