|Scientific Name:||Ardenna creatopus (Coues, 1864)|
Ardenna creatopus ssp. creatopus (Coues, 1864) — Christidis and Boles (2008)
Puffinus creatopus Coues, 1864
|Taxonomic Source(s):||Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.|
|Taxonomic Notes:||Ardenna creatopus (del Hoyo and Collar 2014) was previously placed in the genus Puffinus.|
|Identification information:||48 cm. Large, dull shearwater. Dull greyish-brown head and upperparts. Thinly barred sides of head and neck becoming mottled towards sides of breast. Brownish mottling continues down flanks to merge into bolder brownish lower belly, undertail-coverts and thighs with slight pale mottling. Rest of underparts dull white. Dark mottling on underwing, especially in axillaries, over pale background. Pale pink feet. Yellowish bill with dark tip. Plumage varies between paler and darker morphs. Similar spp. Wedge-tailed Shearwater P. pacificus is smaller and more slender with narrower wings, longer tail and thin dark bill.|
|Red List Category & Criteria:||Vulnerable D2 ver 3.1|
|Reviewer(s):||Butchart, S. & Symes, A.|
|Contributor(s):||Becker, D., Guicking, D., Hodum, P., Morgan, K., Suazo, C.G. & Torres-Mura, J.|
|Facilitator/Compiler(s):||Anderson, O., Butchart, S., Calvert, R., Clay, R.P., Frere, E., Lascelles, B., Moreno, R.|
This species has a very small breeding range at only three known locations, which renders it susceptible to stochastic events and human impacts. If invasive species, harvesting of chicks, bycatch in fisheries or other factors are found to be causing population declines, then the species would warrant uplisting to Endangered.
|Previously published Red List assessments:|
Ardenna creatopus is an east Pacific seabird that breeds only on Robinson Crusoe (a few thousand pairs in 1986 [Brooke 1987]; 2,750 occupied burrows in 2002 [Brooke 2004]; 10,055 burrows in 2016, of which up to 60%  may be occupied [Hodum unpubl. data]) and Santa Clara (2,000-3,000 pairs in 1991 [Brooke 1987] and 4160 breeding pairs in 2016 [Hodum unpubl. data]) in the Juan Fernández Islands, and on Isla Mocha (13,000-17,000 pairs [Guicking et al. 1999], but possibly up to 25,000 pairs [D. Guicking and P. H. Becker in litt. 1999]) off the coast of Arauco, Chile. Recent evidence suggests a small colony on Isla Santa Maria in the Gulf of Arauco, Chile [Hodum unpubl. data]. These sites combined indicate around 30,000 breeding pairs, which would imply a maximum of 100,000 individuals (Brooke 2004). Following breeding, it disperses northward along the west coast of South America towards North America (CEC 2005). There are also isolated records during the non-breeding period in Chilean Patagonia (Imberti 2005, C.G. Suazo in litt. 2016). The migration is evident by its increasing presence along the continental shelf from the Gulf of California in Mexico to British Columbia in Canada, during April and May each year. Numbers peak between August and October, followed by a rapid decline in November, as birds return to their breeding colonies (CEC 2005). Based on ship-based observations, and satellite tracking, Ardenna creatopus ranges from the northern Gulf of Alaska (from approximately 59.87º N) to southern Chile (to roughly 50.00º S); primarily over the continental shelf and slope regions (Mangel et al. 2012, cited in ACAP 2013). A specimen has also been taken from the Atlantic coast of Argentina (Mazar Barnett and Navas 1998) and there are records from New Zealand and Australia (Patterson 1991, D. Guicking and P. H. Becker in litt. 1999). Despite probable declines in the past, populations in the Juan Fernández group appear to have been more or less stable over the past 15 years (CEC 2005, Hodum unpubl. data), although the breeding population on Santa Clara Island increased by 40% following the eradication of European rabbits (Oryctolagus cuniculus) from the island in 2003 (Hodum unpubl. data). In contrast populations on Isla Mocha may be declining owing to the effects of chick harvesting (CEC 2005, although ongoing breeding season monitoring between 2010-2016 suggests a stable population during that time [Hodum unpubl. data]). Birds have been entangled in fishing gear near colonies and in the non-breeding range (Guicking 1999, D. Guicking and P. H. Becker in litt. 1999; Mangel et al. 2012), and this potentially poses a major threat (Guicking et al. 2001, CEC 2005; Mangel et al. 2012).
Native:Canada; Chile; Colombia; Costa Rica; Ecuador; El Salvador; Mexico; Nicaragua; Peru; United States
Vagrant:Argentina; Australia; Guatemala; New Zealand
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There may c. 29,573 breeding pairs (Muñoz and Hodum unpubl. data), which would imply around 150,000 individuals.|
Trends are unknown, although long-term breeding season monitoring on Robinson Crusoe and Santa Clara islands (2002-present) and Mocha (2010-present) suggest stable populations. In addition, a comparison of burrow count data from 2003 and 2016 for all colonies in Juan Fernández indicates that burrow numbers have remained stable during that time (Hodum unpubl. data). Further research is needed to determine if introduced predators and herbivores on Robinson Crusoe Island; rats Rattus spp., dogs and feral cats (Felis catus) and harvesting of chicks on Isla Mocha; and fisheries bycatch are having any impact.
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
Birds arrive at the colonies in early October-November. Eggs are laid in December, with fledging and dispersal in late April-late May (Guicking 1999; Hodum unpubl. data). On Robinson Crusoe, nesting has been recorded in burrows scattered throughout badly eroded, generally sparsely vegetated but occasionally forested habitat at elevations of 50-390 m. On Santa Clara, the species breeds in scattered colonies in eroded terrain at elevations from 15-300m (Hodum and Wainstein 2003). On Isla Mocha, the colony is in forest (predominant tree Aextoxicon punctatum), with the highest burrow densities along mountain ridges and between the roots of old-growth trees up to 390 m (Guicking 1999, D. Guicking and P. H. Becker in litt. 1999). It feeds primarily in offshore waters over the continental shelf but also in pelagic waters (Hodum et al. 2004), mostly on fish (sardines Strangomera bentincki and anchovies Engraulis ringens [Guicking et al. 2001]), squid and to a lesser extent, crustaceans (D. Guicking and P. H. Becker in litt. 1999). Birds breeding on Santa Clara demonstrate a diet dominated by fish, with squid comprising a smaller proportion of the diet (CEC 2005).
|Continuing decline in area, extent and/or quality of habitat:||Unknown|
|Generation Length (years):||18.3|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
Predation by cats Felis catus and coatimundis Nasua nasua on Robinson Crusoe, and cats and dogs Canis lupus familiaris on Mocha (Guicking 1999) may be the most significant threat. Both ship Rattus rattus and brown R. norvegicus rats occur on Isla Mocha; however, their impacts are unknown (Hodum and Wainstein 2003). To date, there is no evidence of rat predation of chicks or eggs on Mocha (Hodum unpubl. data). Chicks are harvested by islanders on Mocha in March-May, with an estimated 20% of all chicks (3000-5000) taken in 1998 (Guicking 1999, CEC 2005). More recently, due to enforcement of the prohibition of chick harvest begun in 2011, the magnitude of the chick harvest has decreased considerably, but quantitative estimates of harvest rates are difficult to obtain (Hodum pers. comm.). European rabbits Oryctolagus cuniculus compete with shearwaters for burrows on Robinson Crusoe but were eradicated from Santa Clara in 2003 with a resultant 40% increase in the proportion of burrows occupied by breeding pairs (Hodum et al. 2017). Soil erosion by goats Capra aegagrus hireus and rabbits affects populations on Robinson Crusoe (Guicking 1999, J. C. Torres-Mura in litt. 1999). At present, due to the highly restricted distribution of goats on the island, their impacts are minimal, in contrast to the pervasive presence of rabbits in all breeding colonies on Robinson Crusoe (Hodum pers. comm.). Cattle Bos taurus in one colony on Robinson Crusoe cause soil erosion and burrow collapses (Gladics et al. in review). Erosion due to vegetation loss causes burrow loss on Santa Clara (Hodum unpubl. data). Birds have been entangled in fishing gear near colonies and in the non-breeding range (Guicking 1999, D. Guicking and P. H. Becker in litt. 1999; Mangel et al. 2012), and this potentially poses a major threat (Guicking et al. 2001, CEC 2005; Mangel et al. 2012). The distribution of longline commercial fishing activities overlap both spatially and temporally with the wintering range of Ardenna creatopus over the continental shelf of North America, making the risk of interaction with the fishing fleet highly likely (CEC 2005). In Chile, small-scale vessels are related to a higher co-occurrence with this species and represent >76% of the overall bycatch (Suazo et al. 2014, 2016). Industrial purse seine is also related to higher level of mortality events, mainly in south-central Chile ( Suazo in litt. 2016). Contamination by chemical pollutants (e.g. mercury) may also be a threat (Becker 2000), as well as plastic debris (Hodum unpubl. data) and oil pollution. Plastic ingestion by Ardenna creatopus has been documented in the Juan Fernández Islands (Hodum unpubl. data). The species is known to raft on the water in large groups in both the breeding and wintering range, which increases the risk of severe mortality from spills, either chronic or major events (CEC 2005). The species is potentially threatened by climate change because it has a geographically bounded distribution: its altitudinal distribution falls entirely within 1,000 m of the highest mountain top within its range (914 m) (Birdlife International unpubl. data).
Conservation Actions Underway
Conservation Actions Proposed
Map revised. Edited: Geographic Range, Population estimates, Threats, Rationale, Conservations Actions Underway and Proposed, Habitat and Ecology, Countries of Ocurrence and Important Conservation Actions and Research Needed. Increase public awareness of, and support for, the species both locally on their breeding islands and at the national level in Chile. The estimated number of mature individual were altered. Added references and also added a new Contributor and Compiler.
|Citation:||BirdLife International. 2017. Ardenna creatopus (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22698195A112079183.Downloaded on 24 January 2018.|
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