An Osprey, Until It Wasn’t

 

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This poor bird was fed fish for WEEKS. Photograph © Jonathan C. Slaght

The latest from my Scientific American series, East of Siberia:

In autumn, 2012, hunters found a young osprey wandering the forest of coastal Primorye. Whereas most of these fish-eating raptors had long flown south for the winter this one walked, dragging its broken wing behind it through the fallen leaves. The hunters chased the bird down, put it in a cardboard box, and brought it to Sergei, a colleague of mine they knew worked for a bird-conservation NGO. By the time the raptor reached him, however, the broken wing had fused. The osprey would never fly again.

I saw this bird for the first time a few weeks later when, checking camera traps to monitor poaching activity along the Maksimovka River, I happened upon Sergei at a field camp. He was there guiding a group of Japanese naturalists on a tour of the region. With no one to leave the osprey with at home, Sergei had brought the bird along, keeping it regularly fed with fish. As a keen angler himself, this was an arrangement that suited both man and bird well. In fact, when I arrived, I saw the large raptor sitting on a stump on the edge of camp, minding its own business, slowly devouring a trout Sergei had recently caught and hand delivered.

Ospreys are uncommon in Primorye. I’d only occasionally seen these fish specialists over the years—adults hovering, then diving for mullet or redfin in the brackish waters of river mouths along the Sea of Japan. And I’d never seen a young one before. From my vantage point across Sergei’s camp, it looked quite different from an adult but had the similar, familiar, black-and-white plumage pattern that adults did.

About a week later I saw the bird again, when Sergei’s caravan of naturalists came to the village of Ternei, where I worked at the Wildlife Conservation Society’s research center. I had offered to describe my work with Blakiston’s fish owls to them and Sergei brought the osprey, perched calmly on his arm, inside the building.

I took a look at this bird under the artificial light of the entryway. The bill didn’t seem right—not blunt and hooked like it should have been—and the whole body shape seemed off. As I scrutinized the bird a little closer it wasn’t long before the osprey farce was obvious. This was not an osprey! It bore only the most superficial resemblance to one.

I’d never seen a raptor like it. Apparently neither had anyone in the group, and it took me a few days to solve the puzzle. It turned out we should have been feeding this poor bird wasp grubs, not fish: this was an oriental honey buzzard. I had trouble identifying it because this was a rare, pale color morph, not the dark-plumaged birds depicted in all the field guides.

This explained how the bird was able to survive for so long in the wild with a broken wing: oriental honey buzzards primarily eat the grubs of ground-nesting wasps and bees. They spy these insects in flight, follow them home, and then raid their nests. Physically, oriental honey buzzards are well adapted to this task. Their long legs are capped by slender toes and elongated talons, which they use to dig out nests, and the plumage on their heads is a dense helmet of stiff feathers that deflect any attacks the wasps might raise.

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Not actually an osprey. Photograph © Jonathan C. Slaght

Armed with this new information, I searched the village stores for honeycomb and took home a honey-soaked block of it about the size of a candy bar. I cleaved this hunk in two and tentatively offered one half to the Bird Formerly Known as Osprey, which reached out a slender leg to gently accept my gift in its needle claws.

It was an odd thing watching a raptor, birds typically associated with evisceration of small mammals or birds, consuming honey with such zeal. The bird concentrated intently, devouring this treat like a boy would an apple, twisting and munching. The honey buzzard looked up at me intently when it was done, like a dog that knows I have more bacon. The final portion was consumed with equal gusto.

How was it that naturalist after naturalist, myself included, had ignored the obvious? When faced with something strange, human minds try to mold the unknown into something familiar, and an osprey was the closest thing that seemed to explain this black-and-white raptor. The red flags that all of us had sensed were explained away by the bird’s juvenile plumage: it will probably look more like an osprey when it gets older, we told ourselves. So: osprey it was. Until it wasn’t.

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The Bird Formerly Known as Osprey, in adult plumage. Photograph © Jonathan C. Slaght

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