The decline of ground nesting birds in Europe: Do we need to manage predation in addition to habitat?

Bird populations are declining globally with losses recorded in many European breeding birds. Habitat management measures have not resulted in widespread reversal of these declines. We analysed national bird population trends from ten European countries (France, Hungary, Ireland, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the UK) for which data on individual bird species was freely available online in relation to the species’ nesting strategy (‘ground-nesting’ or ‘other’), Annex I designation (‘designated’ or ‘not designated’) and association with agricultural habitats for breeding (‘associated’ or ‘not associated’). For each country in our dataset, we also broadly categorised the following factors: farming intensity; predator community complexity; and predator control effort. Our results showed additive effects of nesting strategy, designation, and breeding habitats on the likelihood of population decline. Ground-nesting birds were 86% more likely to decline than birds with other nesting strategies. Annex I designated species of the Birds Directive were 50% less likely to decline than non-designated birds. Birds breeding primarily in agricultural habitat were more likely to decline than birds breeding in other habitats, interactively with farming intensity. Homogenous trends across Europe (i.e. trends in two or more countries that were either not declining in all countries or declining in all countries), indicate that the probability of population decline was related to nesting strategy and breeding habitat. Ground-nesting birds were 15.6 times more likely than other birds to have a declining trend across Europe, and birds nesting in agricultural habitats were 17.8 times more likely to decline than birds nesting in other habitats. Our results highlight a widespread challenge, therefore widespread instruments (e.g. legislation, economic policies, agri-environment schemes) will be required to reserve these declines. Ground-nesting species requirements can be complex and multiple strategies will be needed to restore populations including the development of predation management tools.