A dozen carp swirl in the muddy waters. They are trapped in a shallow pool as the tide recedes, but seem oblivious to their predicament as they feed aggressively on the food-rich sediment. The scaly backs of the biggest break the water. Sea gulls have gathered, as have a pair of great blue herons.
An over-eager heron can’t resist. It grabs one of the big fish and quickly gets the carp’s head in its mouth. But the bird can’t lift the heavy fish, nor does it stand a chance of swallowing the fat 18-incher. The geometry of the situation is irrefutable.
Suddenly, a flash of dark-and-light breaks our field of vision. A rocketing osprey (Pandion Halieaetus), talons outstretched, plucks a slightly smaller carp out of the pool. The bird has a death grip on the fish and is heading for the tree line. Several ring-billed gulls give pursuit, but the osprey shows no sign of slowing or loosening its grip. Gradually, the gulls give way.
Others in the family accipitidae, such as hawks and eagles, feed on fish, mammals, amphibians, reptiles, snails and even insects. Ospreys stop at the first item on the menu. They are called fish hawks with good reason.
Ospreys resemble a cross between bald eagles and sea gulls. They have a wide, 5-foot wingspan and a raptor’s hooked bill. But in flight they look more gull-like, with bent wings and a narrow body. They weigh about 3 pounds, just one-third of what an eagle does.
At first glance, the osprey shows a white head, but a moment later the dark eye patch registers, as does the brown crown. The bird has an almost black back. The wings and tail, when viewed from the top, are a similar hue. Underneath the body is white, and that light coloring extends well out to the crook in the wings. The golden beak and talons of the bald eagle are replaced with dark gray feet and a black beak in the osprey.
The osprey’s hooked bill is well-suited to tearing the flesh away from a fish. But those imposing bills aren’t for killing. That’s a job for its feet. An osprey catches its prey, as we had just witnessed, by swinging its talons forward all the way to the beak just as the bird reaches its prey. Our bird spread its toes wide and grasped the fish with its needle-like talons. The deep puncture wounds and lack of oxygenated water will combine to kill the carp.
Most birds have four toes. They have three forward and the fourth, akin to our thumb, faces back. That’s an ideal set-up for holding on to a perch. But osprey can also rotate one of their front toes backward, so that the bird can effectively grab a slippery fish with a strong, symmetrical hold. The osprey’s talons even have ‘grippers’ on the underside that help them hold fresh fish.
This osprey was likely heading back to the nest. The birds returned to the Chesapeake about a month ago and are now well into the breeding season.
Ospreys usually mate for life and return to the same nest annually. Each year, they refurbish the nest, adding more sticks and a fresh lining of vegetation. Both sexes build the nest, although the male typically brings more materials to the site while the female does the finishing work. They’ll hatch just one brood, usually one or two chicks. The new birds take a month or so to leave the nest.
In the meantime, the parents feed them. The male brings most of the fish to the nest during incubation and before the young fledge. The parents tear off bits of fish for the young, who from their first hours eat fresh fish. Gradually, they will learn to catch prey on their own. But even then, the parents will continue to feed the insistent youngsters for some time.
Ospreys have made a strong rebound from their decimated numbers of 30 years ago. Like bald eagles, ospreys were severely depleted because of hunting, habitat loss and pesticides, primarily DDT. Poisoned birds and paper-thin shells took their toll until protective laws and a ban on DDT saved the species from collapse.
Now the birds continue their strong comeback. Their nests are a common sight, and the platforms that conservationists erect on tall poles and towers near water have been homes to countless new generations.
The bird we had just seen with that big carp in its talons was off to feed itself or perhaps its mate. Another generation seems assured.
Back in the shallow waters, the great blue heron has abandoned the carp. Moments later, the bird grabs a small, wriggling fish instead. The heron deftly flips it into the air and downs it head first.
As a birder, I’m thrilled to see the osprey’s aerial hunting skills and the blue heron’s adroitness. Would I find this scene so fascinating if I knew fish as well as I know birds? Does familiarity alone breed compassion?
For the birds, fish are simply food. But for me, the scene is food for thought.