VU
Phoenix Petrel Pterodroma alba



Justification

Justification of Red List category

This species has a small Area of Occurrence, and is inferred to be undergoing a continued population decline owing to predation by invasive species such as rats and feral cats. Overall rates of decline are however difficult to assess, but the species is estimated to have undergone rapid declines over the past three generations. It is therefore listed as Vulnerable.

Population justification
The most recent estimate for the species's stronghold on Kiritimati is at least 10,000 pairs (Pierce et al. 2020), equivalent to at least 20,000 mature individuals. This is in addition to surveys recording 100 individuals on Hatuta'a in 2010 (Thibault et al. 2013), 12 individuals on Fatu Huku in 2011 (J.-F. Butaud per J.-C. Thibault in litt. 2012), 10 individuals on Canton in 2011 (Pierce et al. 2020), 12-20 pairs on Oeno in 1997-1998 (Bell and Bell 1998, B. Bell pers. comm 1999) and 200 and 300 pairs on Tabu and Upua respectively in 1999 (D. Watling in litt. 1999). The population size is therefore estimated to fall in the band of 20,000-30,000 mature individuals. The subpopulation structure has not been directly analysed. However, as the species breeds on multiple islands, it is tentatively assumed to form multiple subpopulations. Therefore, the largest subpopulation may be that of Kiritimati, and so there may therefore be 20,000 mature individuals in the largest subpopulation.

Trend justification
This species has a long 3 generation length of 34.17 years (based on Bird et al. 2020). The past trend over three generations is therefore calculated using records between 1986-2021. 

The species’s strong hold, on Kiritimati in the Line Islands, was estimated to support 20,000-25,000 individuals between 1980-1982 (Perry 1980, Garnett 1984). In 2007, it was estimated to hold 2,300-3,800 pairs, or 4,600-7,600 individuals (per J.-C. Thibault in litt. 2012). The most recent estimate places the population at over 10,000 breeding pairs or 20,000 mature individuals between 2010-2015 (Pierce et al. 2020). The figures for the 1980s and 2010-2015 are very similar. It has both been suggested that the estimates from the 1980s may have been too high (M. Rauzon in litt. 1999), and that the recent estimate benefited from improved survey methods as well as an increased conservation effort.  

The motus Tabu and Upua (islets in the main lagoon) supported 50 and 40 pairs respectively in 1993 (Jones undated), and 200 and 300 pairs in 1999 (D. Watling in litt. 1999). It is unclear whether the upward trends on these motus are continuing. In the Phoenix Islands, there were >50 pairs on Canton in 1987 (Teebaki 1987). The species was then not found in surveys in the mid-1990s (Flint and Bailey 1995, Flint et al. 1996), and in 2011, less than 5 pairs were estimated to be present (Pierce et al. 2020). In the Marquesas, 5 pairs were present on Fatu Huku in 1990 (V. Bretagnolle in litt. 1999), and in 2011, 12 birds were observed in the area (J.-F. Butaud per J.-C. Thibault in litt. 2012). On Hatuta’a Island, just one individual was observed in 1987 (Thibault et al. 2013). 250 pairs were estimated in 2007, and that decreased to 100 individuals in 2010 (Thibault et al. 2013).

Overall, the population has declined in the past, and this decline is suspected to fall into the band 30-49% over the past 3 generations.

Conservation efforts have likely ceased declines on Kiritimati, and the stronghold population is likely stable (Pierce et al. 2020). However, the species continues to decline elsewhere, and the presence of invasive rats and cats continue to be an issue. Additionally, sea level rise due to climate change is predicted to cause declines by reducing the available breeding areas (Pierce et al. 2020).

Since 1995, restoration work has been undertaken on the islands to reduce the threats, including invasive species removal, and the species now has an Action Plan (Pierce et al. 2020). While it is likely that declines will continue some way into the future, it is not thought that they will reach the high rates previously feared. The stronghold is also considered to be stable (Pierce et al. 2020), so the future rate of decline is not suspected to be so high, therefore placed in the band of 20-29%.

Distribution and population

Pterodroma alba breeds in the Line and Phoenix Islands (Kiribati), Marquesas Islands (French Polynesia), and Pitcairn Islands (to UK) (c.12-20 pairs on Oeno in 1997 and 1998 [Bell and Bell 1998, B. Bell pers.comm 1999]). In the Line Islands, the stronghold is Kiritimati (= Christmas Island). During the non-breeding season, the species disperses over much of the tropical Pacific as far north as Hawaii and as far south as the Kermadec Islands (Gangloff et al. 2009).

Ecology

It nests in colonies on islets or islands at low altitude, often coral atolls or volcanic islands, and feeds mainly on squid, supplemented by fish and crustaceans; it may obtain much food by following cetaceans (Holyoak and Thibault 1984, Carboneras 1992). Records on land are up to 475 m above sea level (GBIF.org 2022).

Threats

Invasive species represent a significant threat to the Phoenix Petrel. Feral cats represent the largest threat (Pierce et al. 2015). The Polynesian Rat Rattus exulans does not seem to predate the species on Hatuta’a Island (Gangloff et al. 2009), but eradications on islets around Christmas Island has resulted in dramatic population increases (R. Pierce in litt. 2016). The introduction of the House Rat Rattus rattus to Christmas Island in the 2000s is of considerable concern (Pierce et al. 2015), but its spread seems to have been relatively slow and it was not thought to have reached breeding islets by 2015 (R. Pierce in litt. 2016). Yellow Crazy Ants also represent a possible threat, with ants known to cause nest abandonment in some burrowing seabirds (Plentovich et al. 2018), but it is not known whether they have reached breeding islets. Feral dogs have also been recorded on the island, and rabbits are known to have had some effect but have since been eradicated (Pierce et al. 2008, R. Pierce in litt. 2016).

Recent monitoring has indicated that bird hunting on some islets around Christmas Island may have switched to this species due to depletion or abandonment of the sites by larger species, with the impact considered locally unsustainable in the short term (Pierce et al. 2015). Commercial and industrial development is not considered a significant threat to the species as no planned development directly impacts the islets on which the species predominately breeds.

Climate change also poses a threat to nesting grounds through sea-level rise and changes in rainfall patterns, which have already affected important seabird nesting areas at Kiritimati (Pierce et al. 2020). 

Conservation actions

Conservation Actions Underway
On Kiritimati, a cat eradication programme has failed to limit predation by feral cats outside villages (M. Rauzon in litt. 1999, E. A. Schreiber in litt. 1999). There are plans to attract the species to cat-free Jarvis Island National Wildlife Refuge (200 miles from Kiritimati) using acoustic playback recorders (Rauzon 1985). On Oeno and Ducie, the Polynesian Rat Rattus exulans was successfully eradicated in 1997 (B. Bell pers. comm 1999). In the Marquesas Islands, there is work ongoing to keep protected areas free of introduced predators (P. Raust in litt. 2012). Biosecurity action plans have been completed for Kiribati, some of the Line Islands, and some of the Pitcairn Islands (Pierce et al. 2020). 

Conservation Actions Proposed
Monitor breeding populations at key sites. Survey for and control invasive species on key breeding islands. Improve biosecurity for key breeding islands. Restore former breeding sites that are currently overrun by invasive species. Restore populations using translocations and audio lures (Pierce et al. 2020), for example to attract the species to cat-free Jarvis Island National Wildlife Refuge (200 miles from Kiritimati), using acoustic playback recorders. Research the species's biology and threats to help guide recovery efforts, and raise local public awareness with regards to the threat of hunting (Pierce et al. 2020).

Identification

35 cm. Medium-sized, dark brown and white petrel. Fairly uniform greyish-brown head, neck, upper breast, upperparts, upperwing and tail. White lower breast, belly and undertail. Brown underwing, with thin white line near leading edge of inner wing. Black bill. Pink legs. Feet pink proximally, black distally. Similar spp. Uniform underwing is distinction from intermediate phases of Herald Petrel P. heraldica and Kermadec Petrel P. neglecta which have white patches. Confusion most likely with Tahiti Petrel Pseudobulweria rostrata, but it is less bulky, has smaller bill, and flies on angled wings without the languor of P. rostrata.

Acknowledgements

Text account compilers
Clark, J.

Contributors
Anderson, O., Bell, B., Bretagnolle, V., Butaud, J.-F., Calvert, R., Fjagesund, T., Hermes, C., Kepler, A.K., Mahood, S., Martin, R., McClellan, R., Moreno, R., O'Brien, A., Piazza, A.D., Pierce, R., Raust, P., Rauzon, M., Schreiber, E.A., Stattersfield, A., Stuart, A., Taylor, J., Temple, H., Thibault, J.-C. & Watling, D.


Recommended citation
BirdLife International (2024) Species factsheet: Phoenix Petrel Pterodroma alba. Downloaded from https://datazone.birdlife.org/species/factsheet/phoenix-petrel-pterodroma-alba on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/11/2024.