Eagle attacks, red invaders and a genetic bottleneck: inside

Captive breeding in Norway has built up numbers endangered by the climate crisis and golden eagles but only a more diverse population will survive in the long term

Deep in the Norwegian mountains, amid a vast expanse of bright snow and howling winds, Toralf Mjøen throws a piece of meat into a fenced enclosure and waits for a pair of dark eyes to appear from the snowy den.

These curious and playful arctic foxes know Mjøen well. He has been the caretaker at this breeding facility for 17 years, going up the mountain daily to feed them at their enclosures near the small village of Oppdal, about 250 miles north of Oslo.