Owl occurrence and calling behavior in a tropical rain forest

Citation
Ple. Rocha et Jl. Rangel-salazar, Owl occurrence and calling behavior in a tropical rain forest, J RAPT RES, 35(2), 2001, pp. 107-114
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
JOURNAL OF RAPTOR RESEARCH
ISSN journal
0892-1016 → ACNP
Volume
35
Issue
2
Year of publication
2001
Pages
107 - 114
Database
ISI
SICI code
0892-1016(200106)35:2<107:OOACBI>2.0.ZU;2-J
Abstract
We estimated owl occurrence (number of individuals per km of trail/night) f rom spontaneous calls and responses to broadcast vocalizations, during 12 r epetitions of each method over 3 2-km nails from April-September 1995 at La Selva Biological Station, Costa Pica. We found Vermiculated Screech-Owls ( Otus vermiculatus, 0.75 owls/km) and Crested Owls (Lophostrix cristata, 1.4 2 owls/km) to be common, and Mottled Owls (Strix virgata, 0.32 owls/km) and Black-and-white Owls (S. nigrolineata, 0.10 owls/km) to be uncommon. Spect acled Owls (Pulsatrix perspicillata, 0.06 owls/km) and Central American Pyg my-Owls (Glaucidium griseiceps, 0.03 owls/km) were rare. When compared to e arlier reports, our results suggested that owl occurrence has changed in re cent years at La Selva Biological Station. Broadcast vocalizations signific antly increased the detections of only Mottled Owls. Detections of all spec ies increased when illumination was less, although this was statistically s ignificant only for Crested and Mottled Owls. Three species were significan tly associated with moon phase. Owl detections tended to be greater during darker periods when the moon was approximately full (either before moon ris e or due to cloud cover). Significantly more Vermiculated Screech-Owls were detected away from the summer solstice, while significantly fewer Crested Owls and Spectacled Owls were detected away from the solstice. Detections d ecreased with time after official sunset, although this was statistically s ignificant only for Spectacled Owls. Our results suggested that changes in owl calling activity was correlated with other species activity, the season of the year, and environmental conditions.