This chapter develops the concept of ‘hunting by profitability’ as a basic principle underlying the hunting strategy of predators. When the birds look for prey (insects) at various hunting sites (niches) in the habitat, they allocate their time among the potential sites according to the profit they can gain at each site (the biomass of prey they can collect per unit effort of hunting). The main objective of this chapter is not to describe the behavioural ecology of the tits as observed, but to show how I made observations, interpreted the results, and inferred the concept of profitability as the basis for the strategy of predators hunting their prey. The concept plays an important role in the analyses of the multi-species interaction processes discussed in Chapters 8 and 9.