This discussion was first published as part of the 2010 Red List update, but remains open for comment to enable reassessment in 2013.
Rufous Crab-hawk Buteogallus aequinoctialis is currently considered Least Concern on the IUCN Red List because it was assumed to have a large global range supporting a moderate population size that was not thought to approach the thresholds for listing as Vulnerable under criterion C of the IUCN Red List, and despite the fact that the population trend appears to be decreasing, the decline was not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion A (>30% decline over ten years or three generations).
However, examination of FAO Forest Resources Assessment Working Paper 63 http://www.fao.org/docrep/007/j1533e/J1533E00.HTM gives a total mangrove cover (this species is a mangrove specialist) of c.30,000 km2 in 1980 from its range states along the north-east coast of South America, and that the area of mangrove habitat declined by over half during 1980-2000 to 1,467,000 ha. A corresponding decrease in the population size over the same time frame (three generations equals 22 years based on a generation length of 7.6 years; BirdLife International unpublished data) could qualify the species as Endangered on the IUCN Red List under criterion A. If declines in suitable habitat have since stabilised the species may now qualify as Vulnerable under criterion A and possibly criterion B if the Extent of Occurrence now constitutes <20,000 km2 and it has been severely fragmented by mangrove clearance.
Comments on current rates of mangrove loss and whether population declines are likely to have occurred at the stipulated rates are welcomed.