A male eagle owl in a quarry near Maastricht has fertilised two females within an hour, in what experts say is a rare case of bigamy for a species normally faithful to a single mate.

Marjon Savelsberg, who has tracked the eagle owls of the ENCI quarry on the Sint-Pietersberg hill for ten years, heard the male mating with his usual partner at 11pm and with a second female some 800 metres away an hour later, she told regional broadcaster L1. She identifies individual birds by their unique territorial calls.

“At first I thought: ‘What a fool!’” Savelsberg said. The male now has to feed two nests of chicks while their mothers keep them warm. “I don’t rule out that we will lose young”, she said.

The first nest has produced three chicks; the second is too overgrown to count.
Eagle owls were hunted out of the Netherlands and most of western Europe over the last century and only returned in 1997, when a pair settled at the ENCI quarry – the founding site of the entire current Dutch population, now estimated at around 80 territories, mostly in Limburg and the east.

Bigamy has been recorded in other owl species, broadcaster NOS reported, but those cases did not end well. “Nature is beautiful, but sometimes it is also harsh”, Savelsberg said.