We start with a general description of the structure of the feeding apparatus in birds (Sect. 17.1), then we describe the biomechanics of those parts (Sect. 17.2), including a review of contemporary approaches to the study of bird feeding morphology and function. We establish explicit links between form and function, and consequent relations to foraging behaviors. In Sect. 17.3, we systematically explore the vast diversity of bird feeding environments by grouping foraging (searching) and feeding (handling—consumption) mechanisms that birds use on land, air, and water. Each one of these subsections addresses not only what birds eat, but also how they feed. We dedicate a separate Sect. (17.4) to drinking because most birds have to perform this process regardless of their diet, and often using different mechanisms than the ones they use to feed. We then discuss evolutionary forces and patterns in bird feeding (convergences, radiations, trade-offs, etc.), including functions different from handling and ingestion that also act to shape the feeding apparatus in birds (Sect. 17.5).