Learning is probably a major contributor to fitness in most animals yet it has not been well integrated into life history research. To quantify the role of learning in shaping lifetime patterns of performance, we must measure learning in natural settings as well as in controlled experimental conditions. As a part of a long-term project measuring the relative contributions of learning, physiology, and effort to observed patterns of lifetime performance, I quantified the foraging success of worker honeybees in the wild. Bees exhibited a four-fold increase in the net rate of food delivery to the colony over their first 4 d as foragers. The major contributors to that pattern were decreases in departure weights and increases in arrival weights. Combined with previous research, this study suggests that learning is the major contributor to the observed increases in lifetime performance, whereas age-specific changes in physiology and effort have a significant though lesser role.