Observed fitness may affect niche overlap in competing species via selective social information use

Social information transmission is important because it enables horizontal spread of behaviors, not only between conspecifics, but also between individuals of different species. Because interspecific social information use is expected to take place among species with similar resource needs, it may have major consequences for the emergence of local adaptations, resource sharing and community organization. Social information use is expected to be selective, but the conditions promoting it in an interspecific context are not well known. Here, we experimentally test whether pied flycatchers (Ficedula hypoleuca) use the clutch size of great tits (Parus major) in determining the quality of the observed individual and use it as a basis in decision-making. We show that pied flycatchers (Ficedula hypoleuca) copied or rejected a novel nest-site feature preference of great tits (Parus major), experimentally manipulated to exhibit high or low fitness (clutch size), respectively. Our results demonst...