Titre du document / Document title

Effects of avian mobbing on roost use and diet of powerful owls, Ninox strenua

Auteur(s) / Author(s)

PAVEY C. R. ⁽¹⁾ ; SMYTH A. K. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Zoology, University of Queensland, AUSTRALIE

Résumé / Abstract

We observed the species and numbers of mobbing birds and their effects on a large, nocturnal, bird-eating predator, the powerful owl, together with the pattern of owl predation on mobbing and non-mobbing species. Owls were mobbed on 35 occasions by seven of 44 species of forest birds at a site composed of open forest (88% by area) and rainforest (12%). The majority of bouts involved individuals of a single species, although mixed groups were observed on nine occasions. Regular mobbers were between 4 and 26% of the owls' body weight. Owls abandoned their daytime roosts during 20% of bouts and responded by calling or actively monitoring mobbers during 54% of bouts. Mobbing appeared to explain why owls roosted in rainforest significantly more often than expected by its availability, mobbing being significantly less frequent in rainforest than in open forest. Only one mobbing species regularly occupied rainforest and the canopy of roosts in rainforest was denser than that in open forest, thus reducing the chances of an owl being detected by potential mobbers. Twelve species of forest birds were within the range of prey size of the powerful owl (75-800 g): six were mobbers and six non-mobbers. The frequency of owl predation on non-mobbers was 8.75 times that on mobbers. The species in this study took a high risk by mobbing a very large predator, but benefited by greatly reducing their chances of predation.

Revue / Journal Title

Animal behaviour   ISSN 0003-3472   CODEN ANBEA8 

Source / Source

1998, vol. 55 (2), pp. 313-318 (22 ref.)

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Kent, ROYAUME-UNI  (1958) (Revue)

Mots-clés anglais / English Keywords

Predation ; Predatory behavior ; Perching behavior ; Diet ; Predator prey relation ; Antipredator behavior ; Vegetation ; Field study ; Queensland ; Feeding behavior ; Feeding ; Environmental factor ; Defensive behavior ; Australia ; Oceania ;

Mots-clés français / French Keywords

Prédation ; Comportement prédateur ; Comportement perchage ; Régime alimentaire ; Relation prédateur proie ; Comportement antiprédateur ; Végétation ; Etude sur terrain ; Queensland ; Ninox strenua ; Mobbing ; Comportement alimentaire ; Alimentation ; Facteur milieu ; Comportement défensif ; Australie ; Océanie ;

Mots-clés espagnols / Spanish Keywords

Rapiña ; Conducta depredador ; Perching behavior ; Régimen alimentario ; Relación depredador presa ; Conducta antidepredador ; Vegetación ; Estudio en campo ; Queensland ; Conducta alimenticia ; Alimentación ; Factor medio ; Conducta defensiva ; Australia ; Oceania ;

Localisation / Location

INIST-CNRS, Cote INIST : 7067, 35400007840813.0060