Conservationists have long been working to keep a rare species of bird from disappearing entirely from the United Kingdom.
But any recent success they've had in protecting the Montagu's harrier's British population can largely be attributed to the mating prowess of one "absolutely prolific" male, says conservationist Mark Thomas.
The 10-year-old stud in question is called AU — the chemical symbol for gold — and he's sired 16 juveniles over the course of his life, including 10 in the last two years.
"He's at the top of his game," Thomas, the species lead for Royal Society for the Protection of Birds (RSPB), told As It Happens guest host Paul Hunter.
"He is single-handedly propping up this species in the U.K. There's no two ways about it."
Montagu's harriers are migratory birds of prey who spend their winters in Africa and parts of Asia, and return to Europe every spring to breed.
Globally, their population is on the decline, and listed as a species of least concern on the International Union for Conservation of Nature's Red List.
In the U.K., the RSPB says, the already rare birds have been rapidly declining, and threatening to disappear from the country altogether.
At their peak in the 1950s, there were about 30 breeding pairs in the U.K., which dropped to zero in the '70s, before rising back to 13 in the mid-aughts. That was followed by another steep decline when there were zero breeding pairs reported between 2000 and 2003.
"We're desperate to try and save the birds we have currently," Thomas said. "And it's been a great year."
After successfully raising four chicks in 2025, the so-called "golden boy" returned again this year to do his acrobatic mating displays in the hopes of catching the eye of some willing females.
"He'll fly to, like, a thousand feet in the air and then he'll do these amazing twist and turns flashing his wings," Thomas said. "The females will then appear. They will chase him around."
This year, Thomas said, three females were fighting for AU's attention.
"The three had a big fight, and they got down to two. And then the two stayed, and nested with him."
AU fathered six chicks between his two mates, four female and two male.
