Caterpillars key to urban blue tits' low breeding

Many animal species suffer reduced reproductive success in urban habitats, despite wide-spread supplementation of breeding and feeding opportunities. In some years, the breeding success of city birds is devastatingly low. Biologists have now shown conclusively that in urban blue tits, reduced breeding success is linked to poor nestling diet and in particular to scarcity of caterpillars, their preferred nestling food. Read more.