The common redstart is a summer migrant associated with mature oak woodland and parkland in Wales and northern England. Its welfare depends on tree cavity availability and a rich invertebrate food chain supported by native oak.
Redstart welfare is tied to the quality of mature oak woodland in which they breed. Ancient woodland with veteran trees provides the nest cavities redstarts require. However, nest site competition with resident tit species means redstart pairs without high-quality territories often fail in their breeding attempts. Provision of nest boxes with entry holes larger than tit boxes (45mm) can increase redstart breeding success in sites with limited natural cavities. The caterpillar food chain supported by oak woodland is critical for chick provisioning — gardens and estates that remove native oaks in favour of ornamental species lose this welfare-critical food resource.