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Flesh-footed Shearwater Ardenna carneipes



Justification

Justification of Red List Category
Despite the poor historical records and the current lack of data across all populations to assess the global population, there is now enough evidence to confirm that its population has been strongly affected by the fisheries operating in Australia and that the population on Lord Howe and Sandy Islands (Australia) and Lady Alice Island (New Zealand) is declining. Based on this evidence, it is suspected that the population has declined by at least 20-29% over three generations. Thus the species is classified as Near Threatened.

Population justification
Brooke (2004) estimated the global population to number >650,000 individuals, but this has recently been revised downward following the identification of a number of significant errors in the historical literature, as well as recent population surveys. Overall, the current global population is substantially smaller than previously thought, comprising only around 74,000 breeding pairs (Lavers 2015). In Australia, the population on Lord Howe Island had been estimated at c.20,000-40,000 breeding pairs in 1978 (Fullagar and Disney 1981) and 17,462 breeding pairs in 2003 (Priddel et al. 2003). In 2009, the population was estimated at 16,267 pairs (95%-confidence interval 11,649–21,250), representing a decline in the number of pairs of 6.8% since 2003, equalling a decline of approximately 1.3% per annum (Reid et al. 2013). In New Zealand, Robertson and Bell (1984) estimated the breeding population at 50,000-100,000 pairs in 1983, while Taylor (2000) considered the population to be at 25,000-50,000 pairs. Recent surveys suggest the population is closer to 10,000-15,000 pairs (Baker et al. 2010, Waugh et al. 2013). The Western Australian population was recently uplisted from Least Concern to Vulnerable (DPaW 2015). Following revision of the breeding population size, the species was recently up-listed to Near Threatened in Australia (Garnett et al. 2011) and to Nationally Vulnerable in New Zealand (Robertson et al. 2013).

Trend justification
Despite the poor historical records and the current lack of data across all populations to assess the global population, there is now enough evidence to confirm that its population has been strongly affected by the fisheries operating in Australia (Tuck et al. 2003, Baker and Wise 2005, Tuck and Wilcox 2008, Richard and Abraham 2014) and the population on Lord Howe and Sandy Island (Australia) and Lady Alice Island (New Zealand) is declining (Tuck et al. 2003, Reid et al. 2013, Waugh et al. 2013, Barbraud et al. 2014).

Distribution and population

This species breeds on St Paul Island (French Southern Territories), Lord Howe Island (Australia), islands off south-west mainland Australia, south Australia (at two isolated colonies), and islands off North and South Islands (New Zealand). In the non-breeding season, it ranges north through the western Pacific Ocean to the seas off Japan, Russia and Korea, with small numbers reaching North America, and north through the Indian Ocean and west to the southern tip of Africa (del Hoyo et al. 1992, Rayner et al. 2011, Reid et al. 2013, Bond and Lavers 2015). 

Ecology

The Flesh-footed Shearwater mainly occurs in the subtropics over continental shelves and slopes, and occasionally in inshore waters. Individuals also pass through the tropics and over deeper waters when on migration to the North Pacific and Indian Oceans (Brooke 2004). Individuals have been recorded over waters of 13–23°C in the south-western Pacific Ocean (Reid 2002) and over waters of 11–16°C in the northern Pacific Ocean (Reid 2010, Reid et al. 2013). Pairs breed on islands in burrows on sloping ground in coastal forest, scrubland, or grassland (Powell et al. 2007). Nests consist of enlarged chambers at the end of burrows (1-3 metres in length), with the entrance often covered by plant material (Waugh et al. 2014).

Threats

Records of bycatch in the Australian Eastern Tuna and Billfish Fishery (ETBF) have been very high; 0.38 birds caught per 1,000 hooks and an estimated 8,972 - 18,490 individuals killed in the period 1998-2002 (Baker and Wise 2005), sufficient to be driving significant declines. Considerable levels of bycatch from gill-nets, purse-seines, longlines and inshore trawl have been recorded across the species’s range (Japan, Australia, Russia and New Zealand) affecting the great majority of the population. Some mitigation methods have been put in place to reduce incidental capture, however the species is repeatedly found to be amongst the seabirds at greatest risk. In Baker and Wise’s (2005) findings, 91% of all birds taken were Flesh-footed Shearwaters. From 1992 to 1996, estimates of seabird bycatch rates on Japanese long-line vessels fishing within the southern Australian EEZ varied between 0.1 and 0.3 birds per 1,000 hooks, with Flesh-footed Shearwaters accounting for around 10% of the observed bycatch (Tuck et al. 2003). An additional 677 Flesh-footed Shearwaters are reportedly taken each year in the Japanese neon flying squid driftnet fishery (Ogi 2008) and 116 in the land-based salmon gillnet fishery (DeGange and Day 1991). In New Zealand, the species is frequently captured in commercial fisheries, ranked as the 3rd (out of 70) most at risk in 2013 (based on estimated annual potential fatalities vs. potential biological removal) (Richard and Abraham 2013), and 5th in 2014 (Richard and Abraham 2014). Mortality in the ETBF has evidently declined in recent years, but this is thought to be largely due to the fishery shifting north in 2006/07 due to a change in the targeted fish species (Reid et al. 2013b). Consequently, high mortality rates in the ETBF may occur again in future years if the fishery returns south. Recreational fisheries bycatch is also likely to be significant (Tennyson et al. 2012). Data on Flesh-footed Shearwater bycatch in the West and South Coast Purse Seine Managed Fisheries in Western Australia (six vessels operated in 2010) suggest up to six adult birds are killed per day per boat (DEF 2005) with more than 512 birds entangled in one season (Dunlop 2007).

Rapid increases in the incidence of plastic ingestion by chicks over the past decade is suspected to be one of the drivers of decline at Lord Howe Island (90% of tested fledglings contained considerable quantities of plastic [Lavers and Bond 2016]) and in other colonies. Preliminary data from New Zealand indicates around 44% of adult birds contain plastic (Robertson et al. 2004). Individuals of all ages have been found to suffer lethal effects. A linear relationship between burrow density and plastic fragments suggests this species is particularly vulnerable to plastic pollution (Buxton et al. 2013). High levels of heavy metal contamination (silver, aluminium, copper, mercury, arsenic and cadmium) have been detected in multiple populations and may be co-pollutants linked to plastic consumption (Bond and Lavers 2011, Lavers et al. 2014, Lewis 2016).

The habit of nesting and roosting in burrows on the ground also exposes the Flesh-footed Shearwater to interaction with terrestrial predators and other competitors. In the late 1930s, predation by Red Fox Vulpes vulpes was deemed responsible for completely eradicating a breeding population from mainland Western Australia (Warham 1958). Introduced House Rats Rattus rattus and Brown Rats R. norvegicus are present in parts of the breeding range and have minor effects on egg and chick mortality, representing an added stress factor on reproductive success (Taylor 2000, Gaze 2000, Pridell et al. 2006). On Breaksea Island, shearwaters compete with rabbits for burrows (Lavers 2015).

Several roads pass through or run adjacent to breeding colonies on Lord Howe Island, and mortalities are frequently reported along the roadsides (Hutton 2003, DECC 2008). The density of carcasses adjacent to roads was 25 times greater than elsewhere in the colony, and an estimated 125 birds were killed on roads during the 2008/2009 breeding season (Reid 2010, Reid et al. 2013a). These rates are sufficient to drive slow population declines (Reid et al. 2013). The number of cars and tourists are increasing on the Island each year, suggesting this is a growing threat to affected populations.

Extensive areas of Flesh-footed Shearwater habitat have been cleared for residential developments up to the recent past. As a result, the extent of suitable habitat on Lord Howe Island was considerably reduced (down 35% from 37.8 ha in 1978 to 24.3 ha in 2002 [Priddel et al. 2006]), but recent restrictions have been reported to have halted further conversion, despite an apparent continued decline in burrow density (Reid et al. 2013).

Conservation actions

Conservation Actions Underway

Lord Howe Island is a UNESCO World Heritage Site. All 42 breeding islands in Western Australia are Class A Nature Reserves.

Conservation Actions Proposed

Work with fisheries to reduce bycatch of this species. Control invasive species that are having a high impact on this species.

Acknowledgements

Text account compilers
Hermes, C., Martin, R., Newton, P., Stuart, A., Butchart, S., Fjagesund, T., Calvert, R., Ekstrom, J.


Recommended citation
BirdLife International (2020) Species factsheet: Ardenna carneipes. Downloaded from http://www.birdlife.org on 22/10/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/10/2020.