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

Taxonomic note
Santa Marta Screech-owl Megascops gilesi is recognised as a species, having first been noted to differ from the rest of the series of M. choliba seen by Todd and Carriker (1922), and finally described by Krabbe (2017). Genetic analysis indicates that it is indeed distinct from other Megascops, with a minimum uncorrected genetic distance of 6.1% (from M. watsonii usta) higher than that recovered between other Megascops species (Dantas et al. 2016). 

Unfortunately the detail of the vocal analysis is unclear as the five taxa for which measured parameters overlap do not appear to be identified, and the differences are not scored (Krabbe 2017). Equally only a description of the plumage is given, rather than a treatment that assesses the differences between taxa. However the sonogram suggests at least a moderately distinctive song, and the phylogenetic position indicated by Dantas et al. (2016) is strong reason to accept that the distinction is indeed a valid full species.

Taxonomic source(s)
Dantas, S.M., Weckstein, J.D., Bates, J.M., Krabbe, N.K., Cadena, C.D., Robbins, M.B., Valderrama, E. and Aleixo, A. 2016. Molecular systematics of the new world screech-owls (Megascops: Aves, Strigidae): biogeographic and taxonomic implications. Molecular phylogenetics and evolution 94: 626-634.
Handbook of the Birds of the World and BirdLife International. 2019. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 4. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v4_Dec19.zip.
Krabbe, N. K. 2017. A new species of Megascops (Strigidae) from the Sierra Nevada de Santa Marta, Colombia, with notes on voices of New World screech-owls. Ornitología Colombiana, 16: 1-27.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	B1ab(iii)

Red List history

Year	Category	Criteria
2019	Vulnerable	B1ab(iii)
2016	Not Recognised
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	4,800 km2
Number of locations	6-10	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	2300-7500 mature individuals	poor	suspected	2019
Population trend	decreasing	-	suspected	-
Number of subpopulations	2-5	-	-	-

Population justification: The population size of this species has not been directly quantified. However, a preliminary population estimate can be derived based on the area of mapped range, habitat availability and population density of congeners. The mapped range (not equivalent to EOO) of Santa Marta Screech-owl covers an area of c.4,500 km². Given that only about 15% of the original forests are remaining in the area, it is concluded that there is c.675 km² of suitable habitat remaining within the range. Density estimates are available for the closely related Tawny-bellied Screech-owl (Megascops watsonii), ranging from 1.75 pairs/km² in French Guiana to 5.5 pairs/km² in Peru (Santini et al. 2018). It is preliminarily assumed that Santa Marta Screech-owl occurs at a similar density, i.e. at 1.75-5.5 pairs/km², which equates to 3.5-11 mature individuals/km². Given the availability of suitable habitat within the range, the population is estimated to number 2,300-7,500 mature individuals.

Trend justification: The forests of the Sierra Nevada de Santa Marta have been heavily logged and burnt since the 1950s, with the cleared land being exploited for non-native tree plantations (primarily pine and eucalyptus) and livestock farming (Dinerstein et al. 1995, Snyder et al. 2000). Only about 15% of the original vegetation of Sierra Nevada de Santa Marta remains. While the rate of forest loss has slowed down considerably, with only minor deforestation occurring between 2000-2016 (Tracewski et al. 2016), the habitat remains fragmented and degraded. Based on this, a slow population decline is suspected.

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

Country/Territory	IBA Name

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	1800 - 2500 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Livestock farming & ranching - Scale Unknown/Unrecorded	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Ecosystem degradation
Agriculture & aquaculture	Wood & pulp plantations - Agro-industry plantations	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Santa Marta Screech-owl Megascops gilesi. Downloaded from https://datazone.birdlife.org/species/factsheet/santa-marta-screech-owl-megascops-gilesi on 23/11/2024.
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 23/11/2024.