Possible causes and consequences of philopatry and breeding dispersal in red-backed shrikes Lanius collurio

Abstract

Studies of animal breeding dispersal have often focused on possible causes, whereas its adaptive significance has received less attention. Using an information-theoretic approach, we assessed predictions of four hypotheses relating to causes and consequences of breeding dispersal in a migratory passerine, the red-backed shrike Lanius collurio. As predicted by the reproductive performance hypothesis, probability of breeding dispersal in females (though not in males) decreased with increasing annual average number of fledglings produced in the past year, but there was no association with conspecific reproductive performance in either sex. The site choice hypothesis, stating that individuals disperse to improve breeding site quality, received support in males only, as dispersal probability was positively associated to a measure indicating low territory quality. The social constraints hypothesis, referring to dispersal in relation to intraspecific interactions, received little support in either sex. The predation risk hypothesis was hardly supported either. Consequences of dispersal were marginal in both sexes because neither fledgling production in females, nor territory quality in males improved after dispersal. In addition, males settled on territories closer to the forest edge than those occupied predispersal, which is opposite to the prediction of the predation risk hypothesis. We conclude that own reproductive success was the major factor determining dispersal behavior in females, whereas territory quality and possibly predation risk were most important in males. Overall, breeding dispersal appeared not to be adaptive in this dense population inhabiting an optimal habitat.

Female breeding dispersal in wolverines, a solitary carnivore with high territorial fidelity

“…2). If insufficient resources were the main reason for females to vacate a territory, we would expect them to have low reproductive success prior to moving (Pasinelli et al 2007). Yet, on seven of nine occasions, the moving females reproduced successfully the last year monitored before vacating her territory (Table 1), which suggests that reproductive failure is not the main factor causing established females to abandon a territory.…”

“…It can also result from intraspecific competition, when resident individuals are evicted or disperse to take over a new territory (Pasinelli et al 2007;Mattisson et al 2013). Breeding dispersal has also been considered as a form of parental investment when the territory is bequeathed to an offspring to enhance offspring survival and reproductive success (Lindström 1986;Berteaux and Boutin 2000).…”

“…Breeding dispersal may be a consequence of reproductive failure, mate loss or an attempt to acquire a higher-quality territory (Wauters et al 1995;Forero et al 1999;Pasinelli et al 2007). It can also result from intraspecific competition, when resident individuals are evicted or disperse to take over a new territory (Pasinelli et al 2007;Mattisson et al 2013).…”

“…did they remain resident or did they permanently leave an established territory. Breeding dispersal may occur to enhance future reproductive success (Wauters et al 1995;Pasinelli et al 2007), or as a consequence of decreased reproductive potential with age (Berteaux and Boutin 2000). Therefore, we considered the influence of previous reproductive performance and age on fidelity for wolverine females.…”

The demography of Yellow WagtailsMotacilla flavaon abandoned fields in northern European Russia

“…Breeding dispersal, survival, and future reproduction may all depend on current reproduction. For example, in passerine birds, unsuccessful breeders disperse more frequently than successful ones (Haas 1998, Sedgwick 2004, Pasinelli et al 2007). Hence, reproductive success plays a central role in the dynamics of a local population, both directly and indirectly (Schaub & Von Hirschheydt 2009).…”