BirdLife species factsheet for Long-whiskered Owlet
Long-whiskered Owlet (Xenoglaux loweryi) is endemic to northern Peru. From discovery in 1976 to the early 2000s, the species had been observed only twice and its life history had been almost unknown. But observations have been more regular during the last decade, shedding light on the distribution and status of the species (Lane and Angulo 2018). Long-whiskered Owlet inhabits a variety of habitats from wet elfin forest to tall forest, bamboo thickets, open woodland and small degraded forest fragments amid pastures (O’Neill and Graves 1977, Fjeldså and Krabbe 1990, Schulenberg et al. 2007, Lane and Angulo 2018). Known records come from 1,900-2,600 m elevation (Lane and Angulo 2018, F. Angulo in litt. 2020). The species is potentially threatened by habitat loss. However, it has been estimated that around 80% of the species’s presumed range are largely inaccessible and comprise pristine habitat (Lane and Angulo 2018).
In the absence of detailed information regarding its status, Long-whiskered Owlet has precautionarily been listed as Endangered under Criteria B1ab(i,ii,iii,v); C2a(ii) (BirdLife International 2020). However, new information regarding the distribution and population trend suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all criteria:
Criterion A – The population trend has not been estimated directly. The only threat known to the species is the loss and degradation of its habitat. Forest loss within the range has been negligible over the past ten years (Tracewski et al. 2016, Lane and Angulo 2018, Global Forest Watch 2020; one generation length being 2.8 years*), and the species is currently not thought to be under threat (Lane and Angulo 208). Therefore, in the absence of evidence for any declines, the species is assessed as stable, and it is listed as Least Concern under Criterion A.
Criterion B – The Extent of Occurrence (EOO) for this species is 2,200 km2. However, as habitat within the range is considerably intact and imminent threats to the species or its habitat appear minimal, the species cannot be considered severely fragmented sensu IUCN (IUCN Standards and Petitions Committee 2019) nor to occur only within a small number of locations**. As such, it does not meet subcriterion a. There does not appear to be evidence to infer a continuing decline nor extreme fluctuation in range size, habitat availability or population size, and thus the species does not meet subcriteria b and c. Even though Long-whiskered Owlet occurs in a small range, it does not meet the threshold for listing as threatened under Criterion B and may thus be considered Least Concern under this criterion.
Criterion C – The global population is thought to be small. However, as it is assessed as stable, the species does not warrant listing as threatened under Criterion C, and therefore qualifies as Least Concern under this criterion.
Criterion D – The population size is preliminarily placed in the band 250-999 mature individuals, and thus the species may be listed as Vulnerable under Criterion D1.
Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.
Therefore, it is suggested that Long-whiskered Owlet (Xenoglaux loweryi) be listed as Vulnerable under Criterion D1. We welcome any comments on the proposed listing.
Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic.
*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).
**The term ‘location’ refers to a distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, with the size of the location depending on the area covered by the threatening event. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).
An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.
Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.
BirdLife International. 2020. Species factsheet: Xenoglaux loweryi. http://www.birdlife.org (Accessed 10 March 2020).
Fjeldså, J.; Krabbe, N. 1990. Birds of the high Andes. Apollo Books, Copenhagen, Denmark.
Global Forest Watch. 2020. World Resources Institute. http://www.globalforestwatch.org (Accessed 10 March 2020).
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. www.iucnredlist.org/technical-documents/categories-and-criteria.
IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categoreis and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.
Lane, D. F.; Angulo, F. 2018. The distribution, natural history, and status of the Long-whiskered Owlet (Xenoglaux loweryi). The Wilson Journal of Ornithology 130(3): 650-657.
O’Neill, J. P.; Graves, G. R. 1977. A new genus and species of owl (Aves: Strigidae) from Peru. The Auk 94: 409-416.
Schulenberg, T. S.; Stotz, D. F.; Lane, D. F.; O’Neill, J. P.; Parker III, T. A. 2007. Birds of Peru. Princeton University Press, Princeton, NJ, USA.
Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.