This discussion was first published as part of the 2013 Red List update, but remains open for comment to enable reassessment in 2014.
Goldie’s Bird-of-Paradise Paradisea decora (BirdLife species factsheet) is currently listed as Near Threatened under criteria B1ab(iii); C1+2a(i); D1, on the basis that it is likely to have a small population, occupying a very small range, which is suspected to be declining owing to habitat degradation; however, its population is not severely fragmented or restricted to a few locations.
Recent data suggest that its population may in fact be very small, being estimated at only c.650 individuals, with a maximum of 500 individuals on Ferguson Island (in six ‘major subpopulations’: Maybole Mountain, Oya Tabu Mountain, Edagwaba Mountain, Sebutuia Bay lowlands, Lavu Lowlands and Lamonai), and 150 individuals on Normanby Island (in five ‘major subpopulations’: Lomitawa, Mount Solomonai, inland Sewa, Lonana and Mount Hobia) (D. Mitchell in litt. 2008).
Bird-of-paradise populations are often very difficult to determine (B. Beehler in litt.), although this species does appear to number far fewer than 2,500 mature individuals, thus potentially meeting the thresholds for Endangered under criterion C2. The ‘major subpopulations’ defined by D. Mitchell (in litt. 2008) could be assumed to form single subpopulations on each island under the IUCN definition of subpopulations, if it is thought that those ‘major subpopulations’ adjacent to one another could exchange two individuals or more per year. This would mean that all subpopulations are estimated to number fewer than 1,000 mature individuals, but not fewer than 250 mature individuals in both cases, thus meeting the subpopulation qualifiers for Vulnerable, but not Endangered.
Overall, the species’s population is thought to be in decline, as evidenced by recent surveys. Declines of c.20% in the ten years prior to 2008 were noted in two subpopulations, one on Ferguson Island and one on Normanby Island, owing to the conversion of habitat to gardens (D. Mitchell in litt. 2008). Habitat loss is continuing, with the resumption of logging in the East Fergusson Timber Rights Purchase area, now in its second of five years of logging (D. Mitchell in litt. 2013). On Normanby Island, mineral exploration is taking place in proximity to populations of this species. In other areas on Normanby, the expansion of subsistence agriculture has recently resulted in the replacement of previously occupied habitat with gardens (D. Mitchell in litt. 2013).
It is therefore suggested that this species could qualify as Vulnerable under criterion C2a(i). Comments are invited on this potential category change and further information would be welcomed.