Abstract
Differential traits, [e.g. feeding at different heights of the trees], have evolved to allow the coexistence of putative competitors, and have been well studied in small passerines (e.g. Paridae) mainly during the winter. However, few studies have been carried out during the breeding season, when competition could be more intense. We applied here a multidimensional approach, including ecological (prey type and size, and nesting habitat characteristics) and life history (timing of maximum nestling food demand) traits which might help to explain the coexistence of great (Parus major), crested (Lophophanes cristatus) and coal tits (Periparus ater) breeding in a Mediterranean pine forest. Great and crested tit nestling diet was equally diverse, and more than that of coal tits. Prey size diversity was similar among species. Great and crested tit consumed longer caterpillars than coal tits. This last species built their nests preferably in nest boxes surrounded by mature vegetation, while great tits preferred immature vegetation; crested tits preferred intermediate vegetation stages. Finally, both great and coal tits overlapped to a great extent their respective breeding cycles, while crested tits bred earlier. Summarizing, each species has a unique combination of niche characteristics which might contribute to the coexistence of the three tit species.
