Improving Our Bird Brains, Part 5: Osprey

Some of the biggest and most beautiful birds my wife and I witnessed while in Florida were ospreys.

Nobody knows what ospreys really are, but scientists call them Pandion haliateus. They’re considered by ornithologists to be one of the most unique birds on the planet. In fact they’re so unique, they belong to their own scientific family (Pandionidae), and genus (Pandion). But no, they’re not related to pandas.

Some scientists claim there are three or four subspecies of osprey. But these subspecies are so similar that other scientists argue they are all the same. Scientists just love to disagree, don’t they? I think they can easily resolve this controversy. A duel with derringers at 20 paces ought to do it.

Ospreys are found on all the continents of the world except Antarctica, where it’s too fucking cold. It’s considered unusual for a single species of animal to have such a widespread distribution, which is one of the things that makes these birds so unique.

Another thing that makes them unique is that they’re piscivorous, having a diet consisting almost entirely of fish. Other raptors feast on a wide variety of prey, but not ospreys. They like fish, they want fish, and they won’t eat anything but fish, unless they’re forced by starvation. Hence, your cats and small dogs are safe in osprey territory.

This means that if you’re looking for ospreys, you must go where the fish are. And that is near large bodies of water, such as the ocean. But they can also be found thousands of miles inland, by lakes and rivers.

An osprey hovering over the Firehole River, at Yellowstone National Park, preparing to dive down and catch a fish.

Another name for ospreys is seahawks. Aside from their talent for fishing, seahawks are regarded for their skills at punting, passing, receiving, and running. But so far they’ve only won one Super Bowl.

Ospreys are huge sons-of-bitches, with wingspans reaching up to six feet. And they have sharper eyesight than your average eagle. They can see through glare on the surface of water, and thus find fish in many different light conditions. There’s no hiding from an osprey.

They’ll fly 30 to over 100 feet above water, briefly hover as they spot an unsuspecting fish near the surface, then plunge feet first into the water and grab the poor bastard. When they hit the water, a nictating membrane closes over their eyes, and valves in their nostrils seal shut. Meanwhile, their well-oiled feathers waterproof them, and keep them from sinking.

An osprey patrolling the waters of the Bahia Honda Channel, in the Florida keys.

Their hooked toes pierce the body of the fish. Each foot has a reversible toe, similar to a human thumb, that works to more tightly grasp the slippery piscine and keep it from slithering away. This is a near-unique feature of ospreys, as no other bird of prey has such reversible toes, except owls.

Their massive wings enable them to hoist fish out of the water that weigh 10% to 50% of their own weight. Most of the fish they catch weigh only about a pound, but some can weigh over four pounds.

Ospreys across the world eat a wide variety of fish, but an individual osprey tends to be a picky eater, concentrating on the two or three types that are most prevalent where it hunts.

After an osprey catches a fish, it carries it so that the fish’s head faces forward, as it transports it to its nest. Bald eagles sometimes mug them enroute, by chasing them down and forcing them to drop their catch.

Ospreys prefer to nest at the tops of trees such as this, at Bahia Honda State Park, Florida.

Ospreys like to nest at the tops of trees and poles. At first they’ll throw a few sticks together, then line them with smaller, finer material. They keep the same nest year-after-year, gradually building it bigger and bigger. By the time they reach old age, which is somewhere around 10 years old, they will have built quite a large dream home for their retirement.

They mate for life and produce one brood of two to four eggs per year. The male goes off and catches fish while his wife babysits. He brings his catch back to her. Then she does all the cooking and feeds the fish to her young. Apparently, ospreys haven’t graduated from the traditional nuclear family structure of the 1950s.

This fledgling osprey seems to be going out on a limb, at Bahia Honda State Park, Florida.

DDT made ospreys an endangered species 50 to 60 years ago, but they’ve made a big comeback since then. So the next time you’re near the ocean, or some other large body of water, keep your eye on the sky and you just might be lucky enough spot one of these unique birds of prey.

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