Justification This species has a small population which breeds within a tiny Area of Occupancy on just one island, and which is continuing to decline. For these reasons it is listed as Critically Endangered.



Taxonomic source(s) Christidis and Boles (1994), Dowsett and Forbes-Watson (1993), Sibley and Monroe (1990, 1993)

Identification 90-100 cm. Huge, mostly black, fork-tailed seabird with white belly and pale bar on upperwings. Adult male has red gular pouch and small white belly patch; long, dark grey, hooked bill. Adult female has black head, throat and spur on sides of upper breast and white collar, breast, belly and spur onto axillaries. Pink bill and red orbital ring. Similar spp. Adult Great Frigatebird F. minor male has all black underparts. Female has dusky throat, black axillaries and lower belly. Adult Lesser Frigatebird F. ariel is smaller with black belly. Immature F. minor has shorter bill and tawny-white head (tawny-yellow in F. andrewsi). Immature F. ariel is smaller and tends to have dark belly. Juvenile F. andrewsi tends to have white lower belly and white spur on axillaries. See James (2004) for detailed notes on identifying frigatebirds.

Population justification The most recent population census indicates a population of 2,400-4,800 mature individuals (D. James in litt. 2003).


Trend justification A historical review suggests that the population declined by around 66% over the last three generations (James 2003), apparently owing to habitat clearance and dust fallout from phosphate mining, marine pollution, over-fishing and bycatch in fishing gear. These declines are projected to continue, and while the introduced yellow crazy ant has not yet been shown to adversely affect frigatebird colonies it undoubtedly represents a serious future threat.