Rigor Vitae: Life Unyielding

Thursday, May 22, 2008


Fishing season officially opens this weekend, but to pull those really big carp from the water, a rod and reel just won't do. What you need is one of these: a Steller's Sea Eagle (Haliaeëtus pelagicus), the biggest member of its genus. This particular bird is a two-year-old captive-bred female that a friend of mine recently acquired. Six more years remain before she'll molt into her full adult plumage of solid dark gray, with a white forehead and tail, and matching "trousers" and "epaulettes." Drab though her current plumage may be, she's anything but unimposing. Her massive 20 pounds assure that; next to her, a Golden Eagle looks like a dark Redtail.

Steller's Sea Eagles range along coastal Siberia, from the Kamchatka peninsula to Sakhalin Island and the Amur River Valley and adjacent China and North Korea, wintering as far south as Japan's Ryukyu Islands. They occasionally wander into the Kodiak, Pribilof and Aleutian Islands, and as far as Midway Island in Hawaii. Apparently, a single bird has been living for several years in Dillingham County, Alaska. Like the Bald Eagle (H. leucocephalus) and the other Haliaeëtus species, Steller's Sea Eagles subsist mainly on fish, which they capture on the wing, scavenge, or strongarm from smaller predators. Ducks, hares, and other non-piscine creatures are taken, possibly more frequently than is generally assumed, and these eagles are hardly above eating carrion or human garbage. Like their two close relatives, the Eurasian Gray Eagle (H. albicilla) and the American Bald Eagle, adult Steller's Sea Eagles have a characteristic white tail, yellow eye and deep, keel-like yellow bill. The Steller's bill is even proportionally larger, almost toucan-like, and the tail is wedge-shaped, with 14, not 12 feathers. It is often held out at a peculiar angle, much like a pygmy owl (Glaucidium spp.) does. When mantling over prey, a Steller's wags its tail about in a unique and somewhat comical fashion. A Korean subspecies, with white tail feathers only, was once proposed, but it was likely just a morph. The minor controversy may never be resolved satisfactorily, since the population was extirpated some 40 years ago.

Steller's Sea Eagles are moderately social, and form strong pair bonds. One or more huge stick nests, which are often rotated periodically, are constructed in trees. In late winter, the female lays two white eggs with a greenish cast. Incubation begins once the second egg is laid, and lasts 35-36 days. Both sexes brood the eggs and young, which begin to fly at about 45 days of age. It seems quite rare for both nestlings to survive to fledging, and siblicide is probably not uncommon.

Eight species of Haliaeëtus eagles are generally recognized. They are less closely related to the typical Aquila eagles than to the kites, particularly those of the genus Haliastur. The widespread, fish-scavenging Brahminy Kite (H. indus - above) of Australasia seems to represent a transitional form between kites and sea-eagles. The three large, northern Haliaeëtus species form a distinct subgroup, and four smaller, tropical species (sometimes placed in their own genus, Blagrus) form another. The eighth species, the Central Asian Pallas' Sea Eagle (H. leucoryphus), exhibits characteristics of both subgroups, and has no very close relatives.
Of the Blagrus subgroup, the Southeast Asian White-bellied Sea Eagle (H. leucogaster - above) is closely related (and considered conspecific by some) to Sanford's Sea Eagle (H. sanfordi) of the Solomon Islands, and the well-known African Fish Eagle (H. vocifer) is likewise closely related to the Madagascan Fish Eagle (H. vociferoides). Another genus of small sea eagles is well-distributed in Southeast Asia, with two species: Icthyophaga humilis and I. icthyaetus.
All Photos by CPBvK


Blogger tai haku said...

Is your friend planning to fly the Steller's at game of some kind? That would be something to see.

I nearly stood on a tame White-bellied sea eagle in Malaysia one night. It had been rehabilitated after someone shot it but couldn't yet fly so it lived on one of the tourist beaches being fed by the locals. I didn't know this when I walked up the beach having just arrived on the island in the pitch darkness and ended up jumping several feet backwards when I unwittingly woke it up. I've probably never been more startled than when that thing started flapping around at waist height out of the darkness!

1:59 PM  
Blogger Carel Brest van Kempen said...

It would indeed be something to see a Steller's fly at game, although managing such a feat would be quite difficult, I imagine. I don't expect to be treated to such a sight any time soon.

10:03 PM  
Blogger Steve Bodio said...

My question exactly-- she could take deer, or Canada geese.

Or salmon!

If I ever get to Salt lake I would love to see this bird.

11:14 AM  
Anonymous Anonymous said...

Thanks for posting this. You've reawakened my interest in Steller and the animals his name has been given too. There is a group of steller jays in my neighborhood that have provided me with countless hours of entertainment watching their behaviors.

8:09 AM  
Blogger Carel Brest van Kempen said...

Steve: Good to hear from you, Steve. I've never known anyone to fly a Haliaeëtus eagle at game, but judging from my contact with these birds in captivity, I'd expect it to be a real pain, especially entering them. I could be completely wrong about this. I know that in the SE US wild Bald Eagles take lots of ducks. Do you know anyone whose flown a sea eagle?
Ajlec: Yes, Steller was an interesting guy all right. There are a couple of books about him. I should read one.

9:44 AM  
Blogger Steve Bodio said...

I know a guy in Saskatchewan who flew a male Bald, quite successfully, on white- tailed jacks. He also flew Ferruginous hawks. I have been a bad inlunce and he is now using the team of saluki and Gyr or Saker.

5:11 PM  

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