Abstract
Data from: Integrating fitness components reveals that survival costs outweigh other benefits and costs of group living in two closely related species. The aim here is to quantify the effect of the group size an individual experiences in a given year on an integrative measure of fitness in two closely related fairy-wrens (Malurus elegans and M. cyaneus). Elegans data were collected in Smithbrook Nature Reserve in Western Australia (34°20′S, 116°10′E) from 2008 to 2016. The main study area comprised 58-70 territories in which >99% of the adult birds were individually colour-banded. Those territories were checked at least fortnightly for group composition and survival throughout the breeding season (Oct-Jan) and once a nest was located this was monitored bi-weekly. Nestlings were blood sampled when at least two days old to determine their sex and parentage using 7 or 8 hypervariable microsatellite markers as described in Brouwer et al. (2011). Cyaneus data were collected at the Australian National Botanic Gardens in Canberra (35°16′S, 149°06′E) from 1993 to 2014. The study area comprised 55-90 territories, in which >99% of the adult birds were individually colour-banded. During the breeding season (Sept-Mar) the complete nesting history and performance of offspring was determined by daily census. Nestlings were blood sampled when eight days old to determine their sex and parentage using 7 or 8 hypervariable microsatellite markers (Double et al. 1997).
