Large-scale spatial distribution of breeding Barn Swallows Hirundo rustica in relation to cattle farming

Capsule: The information on the spatial distribution of cattle farming stored in public bovine computerized databases can predict the distribution and abundance of breeding Barn Swallow Hirundo rustica L. across Europe. Aims: To develop and validate models of habitat factors which account for the distribution of breeding Barn Swallow colonies. Results: The models were based on data on the distribution of cattle farming provided by the public Bovine Computerized Database of the Regione Lombardia (northern Italy). Cattle distribution was a strong predictor of presence and size of Barn Swallow colonies as well as of the number of swallow colonies in a municipality. The models were robust and passed a cross-validation procedure and were used to estimate the spatial distribution of about 116,000 breeding pairs in awide area (8695 km(2)) of the low Po plain of northern Italy in 2001. Conclusions: Bovine computerized databases are mandatory in all European Union (EU) countries according to the EU Regulation (CE) 1760/2000. They may serve as a basis for wide scale modelling of the distribution and abundance of breeding Barn Swallow in Europe.