Montagu's harriers are rare breeding visitors to the UK, nesting in cereal crops across East Anglia and southern England. With fewer than 10 pairs, each breeding attempt is intensively monitored and protected by RSPB nest protection schemes.
Montagu's harrier chicks killed by harvesting machinery die through traumatic injury at the most vulnerable period of their development. Adults repeatedly disturbed at the nest abandon incubation, causing egg chilling and death. The extreme rarity of UK breeding pairs means that each nest failure has disproportionate population significance. RSPB nest protection volunteers who maintain watch at active nests through the breeding season directly prevent welfare harm through early warning of approaching machinery.