Conservationist Mark Thomas recently shared insights in an interview about the efforts to safeguard a rare bird species in the United Kingdom. The success in preserving the British population of Montagu’s harriers, a migratory bird of prey, can be largely credited to a remarkably prolific male known as AU. This 10-year-old bird has fathered 16 offspring, with 10 born in the last two years, earning him the title of the top influencer in sustaining the species in the U.K.
Montagu’s harriers face global population decline and are categorized as a species of least concern on the International Union for Conservation of Nature’s Red List. In the U.K., the birds’ numbers have dwindled significantly over the years. The population peaked in the 1950s with around 30 breeding pairs, dropped to zero in the ’70s, increased to 13 in the mid-2000s, and then sharply declined again with zero breeding pairs reported between 2000 and 2003.
AU’s exceptional breeding success in 2025 and this year has brought hope for the species. His acrobatic mating displays have attracted multiple females, leading to successful nesting and the birth of six chicks, four female, and two male. Conservationists are optimistic that AU’s male offspring will return to the U.K. to continue the breeding cycle, with two males from 2025 already spotted in the country.
The new hatchlings are being carefully protected at two undisclosed nest locations on a British farm, shielded from predators and threats. Satellite trackers have been attached to two juvenile harriers for the first time, allowing researchers to monitor their movements post-fledging and potentially track their return to the U.K. Thomas and his team are eager to analyze the tracking data to better understand the harriers’ migration patterns and breeding behaviors for future conservation efforts.
