In an exclusive interview, conservationist Mark Thomas discusses the remarkable efforts to safeguard a rare bird species in the United Kingdom. The remarkable success in protecting the British population of Montagu’s harriers is largely credited to one exceptionally productive male bird known as AU. This 10-year-old bird has fathered a total of 16 offspring, with 10 of them born within the past two years.
Thomas, who leads the species conservation at the Royal Society for the Protection of Birds (RSPB), emphasized the crucial role AU plays in sustaining the Montagu’s harrier population in the UK. These migratory birds of prey spend their winters in Africa and parts of Asia, returning to Europe each spring for breeding. While globally categorized as a species of least concern, the Montagu’s harriers have faced a rapid decline in the UK.
Formerly boasting around 30 breeding pairs in the 1950s, the UK population plummeted to zero in the ’70s before showing signs of recovery with 13 pairs in the mid-2000s. However, another decline saw zero breeding pairs reported between 2000 and 2003. Thomas highlighted the urgency to protect the current bird population, expressing optimism for the recent successes.
The exceptional breeding efforts of AU have been instrumental in the recent positive outcomes. Following his successful rearing of four chicks in 2025, AU returned this year, engaging in captivating mating displays to attract potential mates. This year, three females vied for his attention, with two eventually nesting with him.
AU fathered six chicks between his two mates, with conservationists hopeful that his male offspring will return to breed in the UK. Two male offspring from 2025 have already been sighted in the country, indicating potential for population growth. The new hatchlings are carefully distributed among two nests, located in a secured area on a British farm.
To ensure the safety of the offspring, researchers have erected protective barriers around the nests to shield them from predators and other threats. Thomas expressed enthusiasm for the conservation efforts, emphasizing the responsibility of safeguarding a species with only two known nests in the UK.
Montagu’s harriers, typically nesting in lowland areas such as marshes and river plains, face risks when forced to nest in farmland. The RSPB actively works to locate these nests, collaborate with farmers, and safeguard the chicks from harm.
In a new initiative, two juvenile harriers have been equipped with satellite trackers for the first time. This technology will enable researchers to monitor their migration patterns and potentially track their return to the UK for breeding. The data from these trackers will provide valuable insights for future conservation efforts, marking a significant advancement in monitoring and protecting the Montagu’s harrier population.