Guadalcanal Owl (Athene granti) | Details

Guadalcanal Owl Athene granti

Current view: Data table and detailed info

Taxonomy

Taxonomic note
Ninox jacquinoti, N. granti, N. malaitae and N. roseoaxillaris (del Hoyo and Collar 2014) were previously lumped as N. jacquinoti following Sibley and Monroe (1990, 1993).

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.

IUCN Red List criteria met and history

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2017	Near Threatened	C2a(ii)
2016	Vulnerable	B1b(v)c(iv); C2a(ii)b
2014	Vulnerable	C2a(ii)b
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Species attributes

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	156 g

Range

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	6,600 km²
Severely fragmented?	no	-

Population

	Estimate	Data quality	Derivation	Year of estimate
Population size	10000-19999 mature individuals	poor	estimated	2016
Population trend	decreasing	-	suspected	-
Generation length	4.1 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification:

The species is only known from a single island of c.5,300 km2, on which its forest habitat is still relatively intact but suffering some losses and degradation. The known home ranges of the intensively-studied Morepork N. novaeseelandiae in New Zealand varies between 3.5 ha (Imboden 1975) and 307 ha (Pryde and Green 2016) depending on habitat productivity, with a representative home range of about 40 ha (M. Pryde in litt. 2016 per G. Dutson in litt. 2016); and similarly Southern Boobook N. boobook in Australia varies from 18 - 206 ha (Olsen et al. 2011). N. granti is heard calling at approximately similar frequencies to these two species in more productive forests (G. Dutson in litt. 2016), suggesting that there might be a handful of pairs per km² of forest. Assuming that over half of Guadalcanal is suitable habitat (see e.g. Katovai et al. 2015, G. Dutson in litt. 2016), the population size of N. granti is precautionarily estimated to be 10,000-19,999 mature individuals (G. Dutson in litt. 2016).

Trend justification: Much of the lowland and hill forests of Guadalcanal have been logged or are under logging concessions. Although the species shows some tolerance of habitat degradation and fragmentation, it is undoubtedly undergoing slow ongoing declines owing to habitat conversion and degradation.

Country/territory distribution

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

Important Bird and Biodiversity Areas (IBA)

Country/Territory	IBA Name

Habitats & altitude

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	suitable	resident
Altitude	0 - 1500 m	Occasional altitudinal limits

Threats & impact

Threat (level 1)

Threat (level 2)

Impact and Stresses

Agriculture & aquaculture

Annual & perennial non-timber crops - Small-holder farming

Timing

Scope

Severity

Impact

Ongoing

Minority (<50%)

Slow, Significant Declines

Low Impact: 5

Stresses
Ecosystem degradation, Ecosystem conversion

Biological resource use

Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]