Population densities of some nocturnal raptor species (Strigidae) in southeastern Peru. Lloyd, H. Journal of Field Ornithology, 74(4):376–380, Dept. of Environ. and Geogr. Sci., Manchester Metropolitan University, John Dalton Extension Building, Chester Street, Manchester, M1 5GD, United Kingdom, 2003.
abstract   bibtex   
Line transects based on distance sampling methodology were used to census nocturnal raptor species in three different primary lowland forest habitats in the Tambopata region, southeastren Peru. Density estimates were calculated for five owl species in these forest habitats. In general, species were more abundant in primary old floodplain or primary middle/upper floodplain forests than in primary seasonally flooded swamp forest. Density estimates were also higher than those calculated from traditional spot-mapping methods in other lowland forest sites in southeastern Peru and French Guiana. There was no significant difference in the number of individual owls recorded during nights with different cloud cover or during different phases of the moon. Problems of distance estimation at night and unfamiliarity with a range of vocalizations, particularly with Strix owls, may be overcome by conducting a practice period before surveys are undertaken, with transect routes and distance markers adequately set out. Walking transect routes during daylight hours in a practice period also helps to overcome concerns of observer safety.
@ARTICLE{Lloyd2003,
  author = {Lloyd, H.},
  title = {Population densities of some nocturnal raptor species (Strigidae)
	in southeastern Peru},
  journal = {Journal of Field Ornithology},
  year = {2003},
  volume = {74},
  pages = {376--380},
  number = {4},
  abstract = {Line transects based on distance sampling methodology were used to
	census nocturnal raptor species in three different primary lowland
	forest habitats in the Tambopata region, southeastren Peru. Density
	estimates were calculated for five owl species in these forest habitats.
	In general, species were more abundant in primary old floodplain
	or primary middle/upper floodplain forests than in primary seasonally
	flooded swamp forest. Density estimates were also higher than those
	calculated from traditional spot-mapping methods in other lowland
	forest sites in southeastern Peru and French Guiana. There was no
	significant difference in the number of individual owls recorded
	during nights with different cloud cover or during different phases
	of the moon. Problems of distance estimation at night and unfamiliarity
	with a range of vocalizations, particularly with Strix owls, may
	be overcome by conducting a practice period before surveys are undertaken,
	with transect routes and distance markers adequately set out. Walking
	transect routes during daylight hours in a practice period also helps
	to overcome concerns of observer safety.},
  address = {Dept. of Environ. and Geogr. Sci., Manchester Metropolitan University,
	John Dalton Extension Building, Chester Street, Manchester, M1 5GD,
	United Kingdom},
  keywords = {Density estimates, Distance sampling, Line transects, Owls, Peru,
	Tambopata},
  owner = {eric},
  subdatabase = {distance},
  timestamp = {2006.11.05}
}

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