Data from: Evidence of low within-pair genetic relatedness in a relict population of Thorn-tailed Rayadito despite long-term isolation

Investigating whether mating patterns are biased in relation to kinship in
isolated populations can provide a better understanding of the occurrence
of inbreeding avoidance mechanisms in wild populations. Here we report on
the genetic relatedness (r) among breeding pairs in a relict population of
Thorn-tailed Rayadito (Aphrastura spinicauda) in north-central Chile that
has experienced a long-term history of isolation. We used simulations
based on eight years of data to assess whether mating is random with
respect to relatedness. We found that mean and median population values of
pair relatedness tended to be lower than randomly generated values,
suggesting that mating is not random with respect to kinship. We
hypothesize that female-biased dispersal is the main mechanism reducing
the likelihood of mating among kin, and that the proportion of related
pairs (i.e., r > 0.125) in the study population (25%) would
presumably be higher in the absence of sex-biased dispersal. The
occurrence of other mechanisms such as extra-pair copulations, delayed
breeding and active inbreeding avoidance through kin discrimination cannot
be dismissed and require further study.