Inbreeding depression should favor the ability of females to avoid inbreeding or minimize its effects. We tested for a relationship between genetic similarity of social pairs and the occurrence of extrapair fertilization (EPF) in the Mexican jay (Aphelocoma ultramarina). Multilocus minisatellite...

Inbreeding depression may drive the evolution of inbreeding avoidance through dispersal and mate choice. In birds, many species show female-biased dispersal, which is an effective inbreeding avoidance mechanism. In contrast, there is scarce evidence in birds for kin discriminative mate choice,...

Social dominance influences the outcome of competitive interactions over limited resources, and may hence be important for individual fitness. Theory thus predicts that its heritability will be low and that non-genetic determinants of dominance should prevail. In this field experiment we...

Individuals of many species differ consistently in their behavioral reaction to mild novel challenges. Suites of these behaviors are referred to as behavioral syndromes or personalities. Personality traits are often phenotypically and genetically correlated. Therefore, animal personalities are...

Individual differences in personality affect behavior in novel or challenging situations. Personality traits may be subject to selection because they affect the ability to dominate others. We investigated whether dominance rank at feeding tables in winter correlated with a heritable personality...

Evolutionary theory of parent-offspring conflict explains begging displays of nestling birds as selfish attempts to influence parental food allocation. Models predict that this conflict may be resolved by honest signaling of offspring need to parents, or by competition among nestmates, leading...

This paper presents the results of an experiment on the influence of changes in flock composition and social rank on the pattern of daily mass gain in captive wintering great tits. We created flocks of three male great tits and scored dominance when ranks had stabilized after a few days. We then...

We measured the selection pressure on brood size in a recently established population of great tits (Parus major L.) in the northern Netherlands by manipulating brood size in three years (1995: n = 51, 1997: n = 66, 1998: n = 51), and we estimated fitness consequences in terms of local survival...

The concept of genetic identity–by–descent (IBD) has markedly advanced our understanding of the genetic similarity among relatives and triggered a number of developments in epidemiological genetics. However, no empirical measure of this relatedness throughout the whole human genome has yet...

We investigated the role of kinship in intraspecific nest parasitism of wood ducks (Aix sponsa). Among waterfowl, female philopatry creates the potential for female relatives to nest in proximity. Costs of intraspecific nest parasitism to host females may be reduced if parasites lay eggs with...