Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Surprisingly, prospecting in active breeders occurs in 85.7% of studied species, and contradicts theoretical models that showed that prospecting is expected to evolve in a relatively predictable and stable environment. Prospecting is more common in populations with frequent inter-annual changes of breeding sites, in species that evolved in ephemeral habitats and among females. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and predict its consequences on fitness at the individual and population levels.