Extent and Duration of Mate Guarding in Swallows Hirundo rustica

Publisher Website
Google Scholar
Abstract
Four mate guarding variables (start of guarding, end of guarding, length of the guarding period, intensity of guarding) were studied in 51 nesting cycles of Swallows Hirundo rustica. Mate guarding was affected by attributes of the male (high body weight and old age leading to guarding ending late) and by external social factors (colonial Swallows starting to guard early, for a long time, at a high rate, but ending earlier than solitary males; less male biased operational sex ratio leading to a low guarding intensity; males starting to guard late in the nesting cycle did so for a short period and at a low guarding intensity, and their female mates experienced more extra-pair copulations than those of other males). Mate guarding may be costly to males, and accordingly those Swallows starting to guard with a high body weight were able to end their guarding period later than other males. Guarding males may incur an opportunity cost by guarding rather than engaging in extra-pair copulations. Male Swallows experiencing less male biased operational sex ratios during their guarding period finished mate guarding earlier than other males.