Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Vocalizations, Distribution, and Ecology of the Cloud-Forest Screech Owl (Megascops marshalli)

Sebastian K. Herzog, Steven R. Ewing, Karl L. Evans, Aidan Maccormick, Thomas Valqui, Rosalind Bryce, Michael Kessler and Ross MacLeod
The Wilson Journal of Ornithology
Vol. 121, No. 2 (Jun., 2009), pp. 240-252
Stable URL: http://www.jstor.org/stable/20616894
Page Count: 13
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Vocalizations, Distribution, and Ecology of the Cloud-Forest Screech Owl (Megascops marshalli)
Preview not available

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.

Page Thumbnails

  • Thumbnail: Page 
240
    240
  • Thumbnail: Page 
241
    241
  • Thumbnail: Page 
242
    242
  • Thumbnail: Page 
243
    243
  • Thumbnail: Page 
244
    244
  • Thumbnail: Page 
245
    245
  • Thumbnail: Page 
246
    246
  • Thumbnail: Page 
247
    247
  • Thumbnail: Page 
248
    248
  • Thumbnail: Page 
249
    249
  • Thumbnail: Page 
250
    250
  • Thumbnail: Page 
251
    251
  • Thumbnail: Page 
252
    252