Variation in the ecological attributes of traditional mating sites defended by male Pintailed (V. macroura, PTW), Shafttailed (V. regia, STW) and Paradise Whydah (V. paradisaea, PW) was analysed using data from a three year study in South Africa. Differences in sexual behaviour at mating sites, and in estimated seasonal mating success (ESMS) of males, were related to variation in male-defended resources. In PTWs, defence of a perennial water source was important to a male's ESMS. Neither body size nor length of breeding rectrices was correlated with ESMS. Female STWs were preferentially attracted to mating sites with a high density of seeding grass, and male intrusion pressure was higher at spatially clumped mating sites than at isolated sites. Twelve STW males were removed from their mating sites. They were replaced by both breeding-plumaged and immature males within as little as 5,5 h, suggesting a significant but limited floating population of potential breeders. Territorial males also moved from sites of low to high sexual activity, presumably in an effort to increase their mating success.