The use and relative importance of intraspecific and interspecific social information in a bird community

Social information, information acquired from other individuals, is used in a wide range of behavioral decisions in many taxa. In nature, individuals usually have access to social information from several species sharing the same habitat, yet social information use from multiple tutor (social information source) species is insufficiently understood. Earlier studies on collared flycatchers (Ficedula albicollis) have piecemeal reported use of both conspecific and heterospecific social information in nest site choices, making it an ideal species to study simultaneous use of conspecific and heterospecific information. Here, we used a previously successful experimental design with abstract geometric symbols as surrogates for tutors’ nest site choices to test the relative importance of intraspecific versus interspecific social information for decision making in collared flycatchers and intraspecific social information use in tits (great and blue tits; Parus major, Cyanistes caeruleus). Due to manipulation and divergent timing of nest site choices, flycatchers were faced with conflicting nest site choices of conspecific and heterospecific (tit) tutors, whereas tits only had access to the choices of tit tutors. In flycatchers, early settling pairs copied even earlier settled heterospecific choices when few conspecific tutors were around, whereas late-settling pairs copied conspecifics when conspecific tutors were numerous in relation to heterospecific tutors. In great tits, pairs with an old male tended to copy the choices of their conspecifics. Our study indicates that birds use flexibly social information from both conspecifics and heterospecifics in different situations, suggesting that perceived niche overlap with potential tutor species affects social information use.