The potential for agri-environment schemes to reverse farmland bird declines is limited for some species by a lack of suitable prescriptions, in particular effective in-field options for species that breed in crops. We assess the provision of alternative nesting habitat for increasing productivity of the Corn Bunting Emberiza calandra. Breeding success was monitored over three years in response to a tailored option that provided extensively managed crops of spring-sown barley, most of which were funded by existing agri-environment schemes and were left unharvested. Corn Buntings nested in both extensively managed crop provisions and conventional intensively managed barley crops. Females that used extensively managed crops for first nesting attempts were almost four times more likely to re-nest, despite their later onset of breeding, than females nesting in conventional crops. The latter rarely produced a second nest and, when they did, usually switched nesting habitat. Extensively managed cereal crops were strongly selected by breeding females and supported a high proportion of the breeding population. A re-nesting model demonstrated that differential re-nesting rates led to 26% higher annual productivity per female in extensively managed cereal crops. Scenario testing illustrated the importance of timely establishment and deferred harvest of these extensively managed cereals. We recommend the provision of unharvested, extensively managed cereal crops as an agri-environment option for Corn Buntings where intensively managed cereal crops are the main nesting habitat.