Competitive Behavior of Birds at Feeders

Publisher Summary This chapter focuses on observing intraspecific (involving members of the same species), interspecific (involving members of different species) competition, and agonistic (submissive and aggressive) communication among locally wintering birds as they forage at stocked feeders. The strongest competition for limited resources arises among members of the same species. Socially dominant members of intraspecific flocks gain access to feeders (and to more protected feeders) over subordinate individuals and dominant flockmates gain access to preferred feeding microhabitats while foraging naturally. Males dominate females in the sexually dimorphic northern cardinal ( Cadinalis cardinalis ). Although less intense than intraspecific competition, interspecific competition for food also adversely affects the foraging behavior of socially subordinate species. Judging on the basis of the dominance relationship between two species, the larger usually dominates. Additionally, bird species that shell sunflower seeds inside their beaks by manipulating the seed with their tongues (such as northern cardinals and finches) usually remain at feeders for extended periods of time, often excluding birds (such as titmice and chickadees) that usually depart the feeder with a single seed to open it elsewhere.