Male nest-building behaviour and mating success in the red bishop (Euplectes orix)

We analysed the relation between male nest-building behaviour and mating success in the red bishop (Euplectes orix), a highly polygynous and colonially breeding weaverbird. Male mating success was mainly determined by the total number of nests built per male during a breeding season, and, to a lesser extent, by the proportion of unusable nests (i.e., nests that became squashed or deformed) per male. The number of nests built increased with longer territory tenures, larger proportions of unusable nests, shorter time delays between consecutive nest-building attempts, and shorter nest-building times. Nests were characterised by the density of fibres in the nest chamber and parameters describing size and deformation. Females preferred nests that were more densely woven and had a larger entrance roof overlap; the latter was also related to nest durability. However, this preference probably reflects only a general rejection of bad nests, since nest characteristics did not differ among males and had no detectable effect on male mating success. Young males had a lower number of nests built, and consequently lower mating success, compared to old males, while there were no differences with regard to other aspects of nest-building behaviour or nest characteristics between the two age groups.