Hokkaido walking tour: Where eagles and cranes dare

I am not a birdwatcher. No judgment, but I have always thought it a bit of an odd way to pass your time. Waiting for hours in the wilderness to catch glimpses of avian life? Flying across the world to see a rare bird, which may have flitted off by the time you arrive? I've just never really understood it.

It's a bit ironic, then, that I have arrived on the northern Japanese island of Hokkaido at the height of its winter birding season. In March and April each year, birders travel the world over to add Hokkaido's iconic residents – especially the Big Three of the red-crowned crane, Steller's sea eagle and Blakiston's fish owl – to their list of sightings.

I, however, am here not for our feathered friends, but to hike across the eastern edge of the island with tour company Walk Japan. And yet, on day one, I find myself inadvertently ticking off my first of the Big Three.

Arriving on Kushiro Mire, Japan's largest remaining marshland, we're greeted by dozens of red-crowned cranes prancing about in the protected area that has helped lift their numbers to 900 today, from near extinction in the 1920s. As we observe them bowing their red crowns and plumping their elegant white bodies, the avian paparazzi crouch beside us in the snow, their ultra-long lenses pointed like sniper guns at a target. As I watch them, I wonder what it is that drives them to pursue this bizarre hobby. Sure, these rare birds are mesmerising, but only for about 10 minutes. These guys look like they've been here for hours, waiting in minus 10 degree temperatures … for what, exactly? To get the perfect shot, when they can already find thousands clogging the internet? Or maybe these photographs are the birder's version of a hunter's carcase? I don't really get it.

What I do get, however, is that these cranes are out of the ordinary. The little brown duck, that our guide is trying to get us interested in as we canoe down the Arekinai River later in the day, is not. As we drift down the narrow channel with a numbered sheet of illustrated birds on our laps, our guide excitedly whispers numbers as he spots the species on the sheet. It's like bird bingo, and it's about as exciting as it sounds. Until the Steller's sea eagle shows up, that is. The most powerful and aggressive eagle in the world, and the second of the Big Three, is perched in a snow-dusted tree just 100 metres away.

Winter brings 2000 Steller's sea eagles – almost a third of the species' population – to Hokkaido each year. With a wingspan of up to two metres and weighing up to 10 kilograms, the Steller's far outsizes North America's bald eagle. But its stunning appearance, with its tangerine beak and talons contrasted against plush black and white feathers, is by far its most impressive feature. It's enough to make us finally reach for our cameras.

Soon the eagle disappears behind us, but as we continue paddling under the sharp blue sky I realise we're now more alert, and that the birdwatching has added extra excitement to our canoeing trip.