• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic note

Puffinus newelli (del Hoyo and Collar 2014) has been split into P. newelli and P. myrtae (Handbook of the Birds of the World and BirdLife International 2018). Martínez-Gómez et al. (2015) found that P. (n). myrtae, ‘Rapa Shearwater’, is genetically more distinct from newelli than newelli is from auricularis. On this basis they propose that myrtae be treated as a full species. Such an arrangement is supported by Shirihai et al. (2017), who noted:

'Rapa Shearwater is much smaller (in all biometric characters) than the other two taxa…, and is furthermore highly distinctive in having a unique combination of white undertail-coverts (vs. dark in both newelli and auricularis) and whitish inner webs to the remiges, as well as a white face.'

Following revised scoring of parsed characters for the differentiation of P. auricularis, P. newelli and P. myrtae, the latter emerges as a very strong candidate for species rank, given that the effect size for wing length vs the smaller of the other two taxa (auricularis), based on Table 3 in Shirihai et al. (2017), is –6.56 (score 3); white vs dark undertail-coverts (at least 2); whitish inner webs to the remiges (at least 1); and a ‘white face’ (impossible to interpret, and in fact not apparent in several photographs online).

We will seek to confirm the characters identified as distinctive by Shirihai et al. (2017) but accept the strong likelihood of at least minor vocal differentiation. Allowing 1 for such an eventuality, and having a score of 6 already on morphological grounds, we tentatively accord myrtae species status as Rapa Shearwater.

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Handbook of the Birds of the World and BirdLife International. 2018. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 3. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v3_Nov18.zip.
Martínez-Gómez, J. E., Matías-Ferrer, N., Sehgal, R. N. M. & Escalante, P. 2015. Phylogenetic placement of the critically endangered Townsend’s Shearwater (Puffinus auricularis auricularis): evidence for its conspecific status with Newell’s Shearwater (Puffinus a. newelli) and a mismatch between genetic and phenotypic differentiation. J. Orn. 156: 1025-1034.
Shirihai, H., Schweizer, M., Kirwan, G. M. & Bretagnolle, V. 2017. The type of Rapa Shearwater Puffinus (newelli?) myrtae from the Austral Islands, Polynesia, with remarks on the morphological variation of the taxon. Bull. Brit. Orn. Club 137: 127-134.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
C2a(ii)	B2ab(iii,v); C2a(i,ii); D	B2ab(iii,v); C2a(i,ii); D1+2

Red List history

Year	Category	Criteria
2018	Critically Endangered	C2a(ii)
2016	Not Recognised
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Migratory status	full migrant	Forest dependency	medium
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	126,000 km2	medium
Area of Occupancy (breeding/resident)	1 km2	medium
Number of locations	4	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	50-249 mature individuals	medium	estimated	2018
Population trend	decreasing	medium	estimated	1964-2010
Generation length	15.5 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: In 1974 the population size was estimated at 265-380 pairs (excluding any potential birds breeding on the main Rapa Island), but no individuals were located during surveys in 1989 (Thibault and Varney 1991). A survey of Morotiri found no individuals of this taxon (Gaskin et al. 2006), and a visit to Rapa in 2017 found only a very small number of individuals (though this was likely not during the breeding season) (S. Cranwell per M. O’Brien in litt. 2018). At sea surveys find the occasional individual, but it appears highly unlikely that there 500-800 mature individuals remaining (M. O’Brien in litt. 2018). The population size is tentatively placed in the band 50-249 mature individuals, equating to 75-375 individuals in total, although it potentially could be lower than this.

Trend justification:

While it is likely that the threats this species faces are causing declines, there is no clear evidence of the rate of decline.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
French Polynesia	extant	native		yes

Country/Territory	IBA Name
French Polynesia	Ilots rocheux de Rapa et Marotiri

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Montane	major	breeding
Grassland	Subtropical/Tropical High Altitude	suitable	breeding
Marine Neritic	Pelagic	major	non-breeding
Marine Neritic	Pelagic	major	breeding
Marine Oceanic	Epipelagic (0-200m)	major	non-breeding
Marine Oceanic	Epipelagic (0-200m)	major	breeding
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Livestock farming & ranching - Small-holder grazing, ranching or farming	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Minority (<50%)		Slow, Significant Declines		Past Impact
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Capra hircus	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Whole (>90%)		Rapid Declines		Past Impact
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Rattus exulans	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Reduced reproductive success

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Recommended citation
BirdLife International (2024) Species factsheet: Rapa Shearwater Puffinus myrtae. Downloaded from https://datazone.birdlife.org/species/factsheet/rapa-shearwater-puffinus-myrtae on 22/12/2024.
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 22/12/2024.