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Crowning Glory: Ringing a special eagle

Crowning Glory: Ringing a special eagle

The day was finally here. For half a year we’d watched the dark Crowned Eagle adults appropriate for themselves an old nest wedged atop a strong fork in a great forest mahogany tree, deep in the Nkumbane River Gorge along the KwaZulu-Natal South Coast. There they did their alterations, constructing a thick platform of branches and sticks some 15 metres above the river bank. Would they breed?

In early September, the male had performed his signature mating display, shattering the usual stillness of the dense forest. Surging way above his regular haunt deep in the canopy, he powered several hundred metres into the sky. Then, folding his broad wings, he’d stoop down at blistering speed, transforming himself from black speck to shrieking missile, skimming the treetops with nonchalant skill. Ten or more times he’d repeat these dives, calling shrilly all the while.

An extra-special chick

Crowned Eagle
Surely the big female, presumably watching these exploits with a discerning eye from her secluded site among the leaves, could not fail to be impressed? And so it was, for she was seen gathering leafy branches to snugly line the nest. And then spent half of September and all of October a virtual prisoner, hunkered down on their eyrie, brooding her eggs. The male would regularly bring her food, and occasionally assume babysitting duties himself as she took a break to stretch her wings, and perhaps do some hunting of her own. Just to keep her talons in practice.

Crowned Eagle parents invest heavily in their young. Generally, two eggs are laid every second year. The firstborn chick, if healthy, invariably outcompetes its younger sibling, which dies of starvation within a few days of birth (yes, they’re eagles, evolved in the furnace of sheer survival to stack the odds in favour of at least one genetic successor). Under ideal conditions of prey abundance, or where a juvenile is lost, a pair might breed again the following year. Exceptionally, twins are raised – the literature contains a handful of such instances.

No one knows exactly when the chick was born, but from early November intriguing reports flowed in of a bobble-headed, fuzzy, white babe closely attended to by the huge, dark mom. Chicks are only able to stand at about five weeks so it wasn’t visible over the lip of the nest from ground-level, along the rugged and distant Gorge Trail of Umdoni Forest Park at Pennington.

However, the Otter View Site along the easier Molly’s Road Trail offers a distant and rather obscured bird’s-eye view of the nest from the top of the gorge. (Eagles are particular about their privacy). With some bodily contortions, much squinting through binoculars and a lot of patience, we could confirm that the eaglet had landed.

Unbeknown to us at the time, this was an extra-special babe. Even more so than any other of its Near Threatened kind. For its mother had been ringed as a chick in 2014 at San Lameer some 72 kilometres down the coast to the south, and this was her first hatchling. In fact, this was the first second-generation research chick recorded born in Dr Shane McPherson’s long-term study on the urban ecology of African Crowned Eagles in the Greater Durban and coastal areas of KwaZulu-Natal.

Sleeping, eating and growing

crowned eagle
With increasing excitement, growing impatience, and not a little anxiety, we glimpsed the chick doing what baby raptors are supposed to do ‒ sleep, eat and grow.  The parents were wonderful. For more than a month the mother was constantly on the nest, a looming magnificence fiercely guarding the frail nestling against any threat, and sheltering it against the elements.

Stepping with unerring precision over and around the youngster, her huge feet ‒ with killing talons to shame a bear ‒ exquisitely placed to avoid trampling, she would accept prey brought fresh to the nest by the diligent father. And, with giant shearing beak, would tenderly feed it just-right-sized strips of warm, raw flesh.

After two months the nestling was almost the size of its father and was beginning to assert some independence. Fully feathered in black-and-white check on its back and wings, and with the pale down almost replaced on breast and belly with snow-white feathers, it would regularly stand tall and proud in the nest, mightily flap its still-stumpy wings and fluff its near-adult tail.

The mother would leave it alone on the nest for increasingly long periods, but would always return, usually with food, much to the shrieking delight of the ever-hungry youngster. By now, mom’s strip-tearing feeding days were over, and the uninhibited chick would launch itself at great chunks of dassie, buck, monkey, hadeda or leguaan. Whatever was on the menu.

The father’s role also had subtly changed from primary provider for mother and chick, to security guard. If we very carefully scanned the forest surrounding the nest tree, we might just spot a solitary, erect, dark shape lurking still and silent within the foliage, some 50 metres away. Zoom in on his head to his intense, all-seeing eyes and we’d know he would never shirk his duties by falling asleep.

He would still do some hunting, but would never alight on the nest. Instead, he’d lay the food on his look-out branch, pinned with a casual foot, and wait for the mother to collect it for herself and the chick. Crowned Eagle fathers have no direct contact with their offspring, except perhaps to help their mate drive it out of their territory when the time has come for the next brood.

They’ll do some part-time egg-incubation when the mother needs a break, and deliver food directly to the nest for about three weeks after the chick is born, leaving immediately after the mother takes it, and never feeding the youngster himself. Thereafter he is not tolerated on the nest, but must wait with food for the mother at the look-out tree.

Timing is important

Crowned Eagle
Impressively large and powerful raptors in their own right, with fearsome talons, the males are considerably smaller than their mates. It is only when you see them together that the true majesty of the 30 per cent larger female is revealed.
There’s a fairly tight window of opportunity to ring these raptors. You want to catch them on the nest before they can fly, for obvious reasons. But even more importantly, you want to catch them before they think they can fly. The thought of one of these rare and beautiful birds jumping out of the nest and crashing to ground with a broken wing or neck, is well, unthinkable.

On the other hand, the thought of fitting a metal ring to an ankle that will outgrow it and damage the foot – the bird’s primary weapon for feeding and defence – is equally so. The magic time is between 70 and 80 days old. The tarsi are fully developed – baby birds, raptors in particular, tend to grow from the bottom up – many sport huge clown feet.

By 90 days the wing and tail feathers are fully grown, the fellow is catching air under his feet when flapping vigorously on the nest, and is probably thinking about clambering to the top of his nest tree to take a short flit. Something he’ll do at about 110 days after hatching.

Gearing up

crowned eagle
So when the ringing day finally dawned to heavy cloud on 17 January, the small group of ‘Eaglers’ gathered at Umdoni Park eco-centre, eager for the long trek through the forest to the view site across the river from the nest tree. But anxious about the weather.

“It should be fine,” said Tammy Caine, shouldering her enormous pack of gear, jaw set in firm determination. As FreeMe KZN Wildlife Rehabilitation Centre’s resident raptor specialist and fully qualified ringer, Tammy knows a thing or two about climbing trees, rain or shine. And ringing raptors. As does her partner, FreeMe KZN’s CEO Wade Whitehead who cheerfully hoisted an even bigger pack.

So off we set with them into the fragrant depths. From across the river, we watched as Tammy and Wade geared up at the base of the nest tree. Our job was to stay inconspicuous, not stress the eagles, keep quiet, but bellow out a warning to Tammy should either of the adults mount an attack.

From the nest, the piebald crowned eagle chick, appearing pretty sanguine, peered down quizzically at the activity below. Of the father, there was no sign, but the mother loomed in a nearby tree, imposing and immobile, moving only her head to constantly sweep us all with her scorching, yellow gaze.

The lead-lines were shot, ropes and pulleys fixed, and Tammy began her long ascent as a gentle drizzle began to fall. The chick couldn’t see her through the thick floor of the nest, had lost interest in proceedings and settled down for a doze. The mother glared.

The killing claw

crowned eagle
A sudden shriek. Tammy free-fell down her ropes, landing hard on her rump. Wasps. She’d disturbed a nest and was quite badly stung. The chick peered. The mother glared. Undaunted, they repositioned the ropes on the other side of the tree, and Tammy bravely began her second attempt. On cue, the rain stopped and the sun came out.

But just below the nest came Tammy and the mother was suddenly there, her two-metre wingspan dwarfing the slight figure on the ropes. Our cries came far too late and, by the time their echoes had faded from the gorge, the mother crowned eagle was gone. And Tammy was still climbing.

It was not a strike, fortunately – the hallux (up to 7cm hind talon), the killing claw driven deep into the body of prey to maximise internal injuries and instantly kill, can do horrible things to the human back – but nevertheless a pass-by so close that Tammy felt the wind of the eagle’s silent passage.

The bagging, lowering, ringing, measuring and return of the chick, a female now dubbed ‘L5’, was accomplished with gratifying professionalism, gentleness and ease. And it was a thrilling morning, leaving us with a newfound respect for the eagles, and people like Tammy and Wade who dedicate themselves to their care.

crowned eagle
For more information about this research, follow Crowned Eagle Research on Facebook @CrownedEagleResearch
FreeMe KZN Wildlife Rehabilitation Centre www.freemekzn.co.za

Pictures Peter Vos, Lennart Eriksson, Paul Johnston, Jane Downey and Tammy Caine

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