Effect of habitat type and nest-site characteristics on the breeding performance of Great and Blue Tits (Parus major and P. caeruleus) in a Mediterranean landscape

Abstrakti

Compared to coniferous forests, deciduous woodlands have often been considered a more suitable habitat for Blue and Great Tits. We compared reproductive parameters of both species in oak woodland and pine plantation patches within a Mediterranean landscape. We found no inter-habitat differences in breeding traits of Blue Tits, but clutches of Great Tits were larger and were laid earlier in the oak woodland than in the pine plantations. However, the breeding success of Great Tits was similar in both habitats, indicating that both species are able to adequately adjust their breeding strategies to conditions of re-cently-colonized habitat, and that these strategies vary between species. At a smaller scale, we found that the clutch size was affected by the dominant tree species surrounding the nests in both species. Laying date in Blue Tits and clutch size in Great Tits was related to the development of the shrub layer, reinforcing the importance of understory over fo-rest avifauna especially in managed monocultures.