Which bird, the world's largest species of owl by mass, inhabits the remote forests of Kamchatka and the Russian Far East, preying on fish and small mammals?

• A Blakiston's fish owl ✓
• B The Eurasian eagle-owl
• C The great grey owl
• D The snowy owl

Blakiston's fish owl (Bubo blakistoni) can weigh over 4.5 kg with a two-metre wingspan and depends on pristine riverine forest, making it an indicator species for intact ecosystems.