In a new lab publication, out today in Proceedings of the Royal Society–Biology, we report our finding that the Metabolic Theory of Ecology accurately predicts the specific increase in total ectoparasite load across birds of different sizes. We also found what appears to be a novel macroecological pattern–a shift in dominance from mites to lice moving from smaller to larger birds–that was only apparent when using total ectoparasite biomass or energy flux. On the whole, the results suggest we’d benefit from using energy flow as a fundamental currency in parasitology (and all ecology), on top of highlighting the possibility of generating unified and efficient scaling theory for parasitism.