Do southern African songbirds live longer than their European counterparts?

Abstract

Understanding life history evolution in tropical and southern hemisphere birds has been hindered by a paucity of knowledge of key life history traits and this is particularly true of African songbirds. Here we use a unique long‐term mark‐recapture data set collected over 16 years in Malawi (latitude 16°S) to estimate adult survival rates for 28 African passerine species. Survival of these and 11 other African songbirds (taken from the literature) showed a bi‐modal distribution with annual survival of insectivores and nectarivores (bulbuls, thrushes, warblers and sunbirds) averaging 72% (quartiles 63–80%) compared to 54% (50–62%) in granivores (weavers, finches and canaries). The mean adult life expectancy of African insectivores and nectarivores (3.1 yr) was more than twice that of related European insectivores (1.4 yr) and nearly twice that of African granivores (1.6 yr). These marked differences in survival were highly significant after controlling for body mass and phylogeny. Among African songbirds there was a strong negative correlation between adult survival and clutch size with granivores laying relatively large clutches and living relatively short lives. We hypothesize that these differing life history trade‐offs reflect variation in the seasonality of food resources whereby survival rates of northern temperate songbirds may be limited by food availability and cold weather during winter, while survival of southern African granivores may be limited by the influence of a variable and unpredictable rainfall regime on seed availability.