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Vocalizations, distribution, and ecology of the cloud-forest screech owl (Megascops marshalli)


Herzog, S K; Ewing, S R; Evans, K L; MacCormick, A; Valqui, T; Bryce, R; Kessler, M; MacLeod, R (2009). Vocalizations, distribution, and ecology of the cloud-forest screech owl (Megascops marshalli). The Wilson Journal of Ornithology, 121(2):240-252.

Abstract

The poorly known Cloud-forest Screech Owl (Megascops marshalli) is a Peruvian endemic
known from only two localities, and its vocalizations have not been documented. We report the first Bolivian
specimen and sound-recordings, an analysis of the species’ longsong in comparison with other brown-eyed
Andean screech owls, and discuss its distribution, natural history, ecological relationships with sympatric congeners,
and conservation status. Longsongs were most similar to those of the allopatric Cinnamon Screech Owl
(M. petersoni) in northern Peru and Ecuador. Principal component analysis of four vocal characters identified:
(1) notable overlap between the two species; (2) some overlap of the Cloud-forest Screech Owl with Ecuadorian,
but not with sympatric Bolivian populations of the Rufescent Screech Owl (M. ingens); and (3) considerable,
evidently clinal geographic variation in the Rufescent Screech Owl. Divergence in vocal characteristics between
the Cloud-forest Screech Owl in Bolivia and other species decreased with increasing geographic distance. The
Cloud-forest Screech Owl is now known from six localities from Departamento Pasco, Peru, south to Departamento
Cochabamba, Bolivia, and has a disjunct distribution with four subpopulations and an overall extent of
occurrence of 12,700 km2. Its preferred habitat is pristine to at most slightly disturbed wet montane forest
with high structural complexity, dense understory, and abundant epiphytes. It has been recorded at altitudes of
1,550–2,580 m, but locally its altitudinal range is 500 m, where it is narrowly syntopic with Rufescent Screech
Owl at its lower and White-throated Screech Owl (M. albogularis) at its upper terminus. Narrowly overlapping
altitudinal replacement in Andean Megascops taxa combined with variable location of replacement zones depending
on local ecoclimatic conditions suggest that species’ distributions are primarily maintained by exclusion
via interspecific competition. The Cloud-forest Screech Owl is currently properly listed as Near Threatened, but
further research may show it is more appropriately categorized as Vulnerable.

Abstract

The poorly known Cloud-forest Screech Owl (Megascops marshalli) is a Peruvian endemic
known from only two localities, and its vocalizations have not been documented. We report the first Bolivian
specimen and sound-recordings, an analysis of the species’ longsong in comparison with other brown-eyed
Andean screech owls, and discuss its distribution, natural history, ecological relationships with sympatric congeners,
and conservation status. Longsongs were most similar to those of the allopatric Cinnamon Screech Owl
(M. petersoni) in northern Peru and Ecuador. Principal component analysis of four vocal characters identified:
(1) notable overlap between the two species; (2) some overlap of the Cloud-forest Screech Owl with Ecuadorian,
but not with sympatric Bolivian populations of the Rufescent Screech Owl (M. ingens); and (3) considerable,
evidently clinal geographic variation in the Rufescent Screech Owl. Divergence in vocal characteristics between
the Cloud-forest Screech Owl in Bolivia and other species decreased with increasing geographic distance. The
Cloud-forest Screech Owl is now known from six localities from Departamento Pasco, Peru, south to Departamento
Cochabamba, Bolivia, and has a disjunct distribution with four subpopulations and an overall extent of
occurrence of 12,700 km2. Its preferred habitat is pristine to at most slightly disturbed wet montane forest
with high structural complexity, dense understory, and abundant epiphytes. It has been recorded at altitudes of
1,550–2,580 m, but locally its altitudinal range is 500 m, where it is narrowly syntopic with Rufescent Screech
Owl at its lower and White-throated Screech Owl (M. albogularis) at its upper terminus. Narrowly overlapping
altitudinal replacement in Andean Megascops taxa combined with variable location of replacement zones depending
on local ecoclimatic conditions suggest that species’ distributions are primarily maintained by exclusion
via interspecific competition. The Cloud-forest Screech Owl is currently properly listed as Near Threatened, but
further research may show it is more appropriately categorized as Vulnerable.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Systematic and Evolutionary Botany
Dewey Decimal Classification:580 Plants (Botany)
Language:English
Date:2009
Deposited On:19 Jan 2010 15:04
Last Modified:05 Apr 2016 13:37
Publisher:Wilson Ornithological Society
ISSN:1559-4491
Publisher DOI:https://doi.org/10.1676/08-041.1
Official URL:http://www.bioone.org/doi/abs/10.1676/08-041.1

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