Social and habitat associations of sympatric Coal Tits Periparus ater and Marsh Tits Poecile palustris in native broadleaved forest
Authors: Broughton, R.K., Maziarz, M., Hill, R.A., Melin, M. and Hinsley, S.A.
Conference: European Ornithologists' Union conference 2017
Dates: 18-22 August 2017
Abstract:Winter food-hoarding behaviour in birds is generally associated with a well-defined social structure. In the food-hoarding parids, such as the Willow Tit Poecile montana, Coal Tit and Marsh Tit of Europe and the chickadees Poecile spp. of North America, winter flocks typically have a stable membership of individuals with strong social bonds and who defend a communal home-range against conspecifics. This ‘discrete flock’ structure contrasts with the ‘basic flock’ system of non-hoarding species, such as the Great Tit Parus major and Blue Tit Cyanistes caeruleus, where flock membership is weak and transitory. Most studies of food-hoarding parids come from northern latitudes, however, and there is some evidence that social organisation in these species could be more diverse than was previously thought. In particular, studies of Spanish Coal Tits and English Marsh Tits appear to show a more ’basic flock’ structure than is reported from Scandinavia, suggesting a differing social arrangement at lower latitudes. We present new data on the social organisation and habitat use of sympatric Coal Tits and Marsh Tits in English deciduous forest. We show how both species have a pair-based social system with breeding territories defended against conspecifics, but have winter home-ranges that overlap within and between species, with little evidence of stable membership of mixed or single-species groups. We compare these results with other studies, discussing the implications for understanding the relationships between social organisation, food hoarding, habitat and climate, and call for further studies from Eurasia and North America to address these fascinating questions.
Source: Manual