The Steller's Sea Eagle (Haliaeetus pelagicus), is one of the largest and most fierce diurnal birds on Earth; and they are the main reason why my Hokkaido Birding Nature Photo tours are so popular. These eagles are huge, on average, the heaviest raptor on our planet, weighing up to 10 kg (22 lb). They are also tall, measuring up to 94cm (3 ft), with a huge wingspan of up to 250 cm (8.2 ft). Their plumage is blackish brown-black all over except on the shoulders, rump, tail thighs, and forehead, which are white. Their big bill is yellow and wickedly hooked, with raw force, they quickly slice through the flesh of their prey and devour it. The eagles are masters at fishing. It’s incredible to watch as they swoop down and catch fish with their huge razor sharp talons. However, the Steller’s Sea Eagle used to be just one among many others raptors. Haliaeetus pelagicus has survived three ice ages without the need to evolve, while other raptor species have gone extinct. One example of this is Haast’s Eagle (Hieraaetus moorei), said to be endemic to the south island of New Zealand, with a history reaching back more than 2 million years, until its extinction around 1400. The Female Haast’s Eagles were significantly larger than their male counterparts ranging from 10–15 kg (22–33 lb) while the males were around 9–12 kg (20–26 lb). Haast’s Eagles had a relatively short wingspan for their size. It is estimated that the grown female typically spanned up to 2.6 m (8 ft 6 in), possibly up to 3 m (10 ft) in a few rare cases. Haast's eagles were massive eagles, but they only outweighed the Steller’s Sea Eagle 1.5 kg (3 lb) being 11.5 kg (25 lb) for males and 14 kg (31 lb) for females.
Part of the Steller’s Sea Eagle evolutionary success may be their narrowly defined habitat and hunting grounds. The Steller's sea eagle is endemic to Northeast Asia, and is thought to only breed in on the shorelines of the Sea of Okhotsk and Bering Sea, due to its rich fresh and saltwater fishing grounds. But during late autumn, the Steller’s sea eagles venture to a slightly warmer climate and better winter fishing grounds of Hokkaido, Japan, so if the Steller’s sea eagle photo op is what you’re after, you’ll need to make the pilgrimage to Hokkaido to make your dinosaur raptor dream a reality, and as many professional birding photographers know, a local or well-experienced Hokkaido workshop leader or guide is a necessity. I have spent over 20 years photographing in Hokkaido, and I have photographed Steller’s Sea Eagles and their perpetual adversary, the White-tailed Eagle (Haliaeetus albicilla), on hundreds of occasions. However, Haast’s Eagles struggled with a different adversary, the Maori people of New Zealand. Haast’s Eagles main prey were Moa (Dinornis novaezealandiae) a huge flightless bird endemic to New Zealand, but when the Maori arrived, they began to hunt the same bird to such a degree that it became extinct. With its main source of prey gone, Haast’s Eagles became extinct about the same time as the Moa on New Zealand. This is where the two eagles greatly differ. The Steller’s Sea Eagles have a varied diet and approach to predation. During long winter storms along the Hokkaido Pacific coastline, young human children and house pets such as dogs and cats are carefully watched when venturing out on their own, that is when the Steller’s Sea Eagle’s food supply becomes scarce. There are even fables of children going missing during these periods due to insufficient safety protocols being followed. It’s far too common that cats, dogs, and some young livestock and even deer go missing when there’s foul weather, and the fishing is slow. These raptors have even been known to attack the Ezo Red Fox (Vulpes vulpes schrencki), the Red-Crowned Cranes (Grus japonensis), Whooper Swans (Cygnus cygnus) and are always seen in conflict with the fourth largest raptor on our planet, the White-tailed eagle, that hold their own against these larger raptors.