Sex and Age Affect Vulnerability of Desert Rodents to Owl Predation

Absence of Differential Predation on Rats by Malaysian Barn Owls in Oil Palm Plantations

“…Nonselective predation by Barn Owls may be attributable to a lack of differences in the vulnerability of different classes of prey (Longland andJenkins 1987, Vassallo et al 1994). Without information on movement patterns of R. r. diardii, we cannot determine whether the nonselective predation by Barn Owls at our site was due to the ranging behavior or social structure of the prey, which may in turn lead to a nonrandom distribution of dominant and subordinate individuals in an area.…”

“…A predator that selectively feeds on sex or age classes may skew population sex ratios, reduce reproduction, or alter the social structure of prey populations (Longland andJenkins 1987, Andreassen andGundersen 2006). Selection of certain prey groups is often associated directly with the morphology and behavior of the prey (Derting and Cranford 1989) and indirectly with habitats (Trejo and Guthmann 2003).…”

“…For example, strongly territorial individuals may travel shorter distances (Vassallo et al 1994, Bellocq 1998, whereas juvenile small mammals tend to disperse further (Sinclair et al 1990), thus making them more vulnerable to predators. Differential predation has been described in numerous owl species, e.g., Short-eared Owls (Asio flammeus; Blem et al 1993), Eurasian Eagle-Owl (Bubo bubo; Donazar and Ceballos 1989), Great Horned Owls (Bubo virginianus; Longland andJenkins 1987, Rohner andKrebs 1996), and Eastern Screech-Owls (Otus asio; Marti and Hogue 1979). Several studies of Barn Owls have described their tendency to feed on either smaller (Dickman et al 1991, Leonardi and Dell'Arte 2006, Granjon and Traoré 2007 or larger prey (Derting andCranford 1989, Castro andJaksic 1995), depending on seasonal changes in prey populations or habitat conditions.…”

Small Mammal Prey Selection by Two Owl Species in Southeastern Brazil

“…Some researchers have suggested that selective predation based on sex or conspicuous characteristics may alter prey sex ratios or social structure (Roberts andWolfe 1974, Longland andJenkins 1987). Morphological and behavioral variation in both prey and predators may explain selective predation (MacArthur and Pianka 1966, Griffiths 1980, Greene 1986).…”

Selective predation on common voles by Tawny Owls and Long-eared Owls in winter and spring

“…Some authors (Fulk, 1976;Lagerström and Häkkinen, 1978;Korpimäki, 1985;Halle, 1988) found that owls catch young rodents and male shrews. Others (Longland and Jenkins, 1987;Dickman et al, 1991) wrote that young females were more vulnerable in populations of many rodent species. According Marti and Hogue (1979), A. otus selected small laboratory mice in preference to large ones, although owls do not hunt voles weighing up to 5 g (Goszczyński, 1977).…”