Eagle-owls are elusive, which makes them difficult to study in their natural habitats. In south-eastern Spain, scientists monitored 72 Eurasian eagle-owl territories between 2006 and 2012. From 2004 to 2012, they monitored 253 territories from ten subpopulations in the Iberian Peninsula. A scientist counts a successful pair as one that raised at least one young until it was 50 to 60 days old.
Owl pellets are very useful to scientists because they help them understand what these hard-to-find birds eat. A pellet is a small ball of hair, feathers and bones that an eagle-owl could not digest. Eagle-owls eat many kinds of animals, from beetles to fawns. A pellet study in southeastern France found that the pellets showed a broad dietary range, which reflects the generalist predator behaviour of the Eagle Owl.
Scientists who modelled eagle-owl territories in Spain found that what happened in one year mattered most. Breeding success in a territory was the most important factor in whether it was used again and bred successfully the next year. The same study found strong changes in success from year to year. These changes may be related to changes in the number of European rabbits, the eagle-owl's main prey. Scrub areas favour rabbits, which helps eagle-owl breeding success.
Scientists writing about south-eastern Spain say eagle-owls have small home ranges and a movement pattern based on short flights. Home ranges vary in size with habitat structure and composition, the owl's sex and its state of health. In Norway, GPS satellite transmitters on seven adult eagle-owls showed a mean home range of 42.9 square kilometers for breeding adults. Five of the seven made long excursions of more than 20 kilometers away from their breeding territories during autumn. The Norwegian authors say this wide-ranging behavior had not previously been reported for adults of the nominate subspecies.
In Europe, the Eurasian eagle-owl's numbers fell in the first half of the 1900s. As of November 2026, the Peregrine Fund says they are recovering but have not returned to what they were before the mid-1900s. Unlike most large raptors such as eagles or vultures, the eagle-owl has high reproductive rates, which may have favored a rapid recovery in Spain.
Chicks grow quickly, and they feed themselves at three weeks and fly short distances by about 52 days. A zoo raptor group says eagle-owl young are independent at 150 to 160 days of age, and they usually stay in their parents' territory for another 3 to 4 months before looking for a territory of their own.
Words to know
- subpopulations: smaller local groups
- elusive: hard to find
- excursions: long trips
- raptors: birds of prey
