No cultural transmission of use of nest materials in titmice Paridae

Abstract

Bird nests often consist of stronger materials to maintain nest structure and a softer layer of lining materials to reduce heat loss. We studied whether early learning affected the use of nest materials by cross-fostering between two tit species with similar breeding ecology, the blue tit, Cyanistes caeruleus, and the great tit, Parus major, in a woodland area provided with nestboxes in Norway. In both species, only the female builds the nest. From previous studies, we know that early social learning affects a number of traits in these birds, including song repertoire, mate choice, foraging behaviour and nest site choice. Nests of the two species are similar but blue tits use more feathers than great tits. This was confirmed in the present study; however, female blue tits raised by great tit foster parents also supplied their nest with feathers, and female great tits raised by blue tits used few feathers. The only treatment effect was that fewer feathers were found in nests of cross-fostered females in both species than in nests of controls. This may have been caused by time and energetic constraints during nest building because cross-fostered birds seemed to forage less efficiently than controls. The amount of hair was slightly greater in blue tits than in great tits, but it was not affected by the cross-fostering either. We conclude that no cultural transmission was found in the use of lining materials in the nest of the two species, perhaps because young birds hatch after their parents have stopped constructing the nest.