Conservationist Mark Thomas recently shared insights in an interview about the efforts to protect a rare bird species in the United Kingdom. The successful preservation of the Montagu’s harrier population in Britain is largely credited to one remarkably fertile male bird known as AU. This 10-year-old male, nicknamed after the chemical symbol for gold, has fathered a total of 16 offspring, with 10 born in the last two years.

Thomas, who leads the species conservation at the Royal Society for the Protection of Birds (RSPB), emphasized the significant role AU plays in sustaining the species in the UK. Montagu’s harriers are migratory birds that winter in Africa and parts of Asia, returning to Europe for breeding each spring. Despite being classified as a species of least concern globally, their numbers have been dwindling, especially in the UK.

The decline in the UK’s Montagu’s harrier population has been a cause for concern, with the species facing the risk of disappearing from the country. Thomas highlighted the species’ turbulent history in the UK, noting that while there were around 30 breeding pairs in the 1950s, the numbers plummeted in subsequent decades. However, recent successes in breeding efforts have shown promise, thanks in part to AU’s remarkable mating success.

AU’s impressive track record includes successfully raising four chicks in 2025 and fathering six more this year. Conservationists are optimistic about the future, hoping that AU’s offspring will return to the UK to continue the breeding cycle. To protect the new hatchlings, researchers have taken measures to safeguard the nests, with the exact locations kept confidential.

In a bid to monitor the young harriers’ movements, the RSPB has equipped two juvenile birds with satellite trackers for the first time. This tracking initiative aims to provide valuable data on the birds’ migration patterns and potential return to the UK for breeding. Thomas expressed eagerness to analyze the tracking data to further enhance conservation efforts for the Montagu’s harrier species.