Zimbali Coastal Resort

Invitation article by

Geoff Nichols

Environmental Consultant to Zimbali Coastal Resort

Zimbali Coastal Resort, encompasses 456 hectares – originally 70% forest (a combination of natural forest, sugarcane fields, and plantations of Casuarina and Gum trees) and 30% cultivated land – has, with careful planning and eco-sensitive development, been transformed into 85% development and 15% forest.  Owing to the ethos “living in harmony with nature”, Zimbali has matured into a protected natural environment comprising ecological richness and biological diversity.

The developed areas of the estate include private gardens, verges and the golf course – all of which provide refuge to the wide array of birds and animals that would otherwise be unable to inhabit the estate. Although the wetlands have remained intact, Zimbali has lost several “specialist” bird species (mostly due to human disturbance during the early development stages). A number of “generalists” have since taken their place.

Due to the success of the estate’s strict conservation policy, Zimbali Coastal Resort has acted as a conservancy for the re-establishment of many threatened indigenous species, providing a secure home to a variety of local flora and fauna, including over 220 species of bird and no less than 34 species of mammal. Zimbali Coastal Resort has been awarded two environmental accolades: the Nedbank/Mail & Guardian Green Trust Award in the corporate award category (Moreland Developments, 2000); and the more recent award from South African Landscapers Institute(SALI) for the Best Environmental Landscape Work in South Africa (Leitch Landscapes, 2010).

Zimbali Coastal Resort’s habitable environment supports a variety of predatory birds known as raptors. In order for these birds to survive at the top of their food chain and breed, all the other links in this food chain or pyramid must be intact or the raptors will be forced to relocate to a more suitable environment.

There are only about 25 individual birds that prey on other creatures in Zimbali, namely a pair of Crowned Eagles, a pair of African Fish Eagles, two pairs of Yellow-billed Kites that nest on the estate, a pair of Black Sparrowhawk, a pair of African Goshawks, a pair of Little Sparrowhawks, and approximately five pairs of Spotted Eagle Owls.

A single Long-crested Eagle is often seen sitting on posts along the road reserve verges of the M4 provincial road on the west boundary of Zimbali. Among other visitors is an African Harrier Hawk attacking Village Weavers at their nesting colony, as well as Little Swifts colonies under the bridges.

The two raptors most regularly encountered are the African Crowned Eagle and the African Fish Eagle; the former identified by its steep, undulating aerial displays, and the latter by its yelping, echoing call over its open water hunting habitat. Also, the African Goshawk with its high  aerial displays above the forest canopy at dawn and dusk while uttering its chik-chik-chik call every few seconds before folding its wings and plunging back down into the canopy.

Besides covering a large area, Zimbali also features sufficient intact coastal lowland forest to support the requisites of a pair of Africa’s largest forest raptor, the African Crowned Eagle. These majestic birds breed approx. 25m from the ground, within view of visitors to the Fairmont Zimbali Lodge. Their aerial mating display is a steep diving, undulating affair high above the forest which is accompanied by their loud yelping call. To hear this evocative call is a spectacular experience.

The pair of African Crowned Eagles returned to Zimbali to breed during the 2001 and 2002 breeding season, and has since fledged nine chicks. These birds only produce one chick per breeding cycle. They prey primarily on Vervet Monkeys and Blue Duiker that they ambush in open glades or verges in the forest. For them to successfully fledge a young eagle there has to be enough food to feed both the parents and the young fledgling. This pair has become quite habituated to humans watching them.

Zimbali has also the most varied set of prey items of any of the urban adapted eagles studied as part of this work. Shane McPherson has identified that, "The parent eagles delivered 87 prey animals to the young eaglet during approximately five months of camera-monitoring. The primary prey includes Vervet Monkeys, Blue Duiker, and Hadeda Ibis nestlings. Prey of secondary importance includes several cane rats, galago's (bushbabies) and mongooses. Interesting one-off records include a young bushbuck, a crested guineafowl, a dove squab, a golden mole, and an owl as well!”

These eagles have given Zimbali Coastal Resort the best environmental achievement award in that the variety of prey items is a reflection of the varied and rich biodiversity of other birds and mammals that live and breed amongst humans.

Spotted Ground Thrush at Zimbali

Mother-of-pearl at Zimbali

Crowned Eagle at Zimbali

The nest was best visible from the roof of the Fairmont Lodge in 2012

Pruning has opened the view to the nest from the Fairmont Lodge balcony for 2013

Installed camera

Happy family

Sharing a table

Egyptian Goose below the Crowned Eagle nest

I knew very early on in the season that Egyptian Geese had an interest in the Zimbali crowned eagle nest.  On the 25th of September, even while the eagles were incubating, I observed a pair of geese flying up to branches on the underside of the nest, at first I thought they were trying to steal nesting material, but they were probably trying to steal the entire nest.  Fortunately the female eagle sat strong and steady and the geese backed off. I have no record of the geese interactions during the incubation period and the first 20 days of chick rearing, I only suppose that the eagles were very forceful or the geese wisely cautious.  And during the months after the camera was installed, while the young eagle was flightless and sedentary on the nest, there were no incidents observed. On the 18th of December the eagle chick was ringed with a yellow N2 band, she was measured as a large female and returned to the nest. N2 fledged at about 115 days of age around the 26th of January.

After fledging, young crowned eagles are still completely reliant on the adults for delivering food, and unlike many other raptors which will chase and steal prey from the incoming adults crowned eagle fledglings wait courteously on the nest for the food to be served.  This can go on for five months post-fledging and so my diet studies using the cameras continue for months after.

I timed my next camera service once the young eagle had made its first flight, and didn't notice anything unusual - unknown to me at the time was that the first few eggs of the clutch were deceptively hidden, covered by the detritus of nesting material .  On the next camera maintenance visit three weeks later the goose nest was obvious, lined with goose down, and again the eggs were deceptively covered.  I got a hell of a fright when one of the geese swooped past me and landed on the nest hissing with fury  -  I thought it was one of the eagles!  I laughed as the adrenaline rush of fear gave way to amused chagrin at the silly goose.

Silly goose on the left !

In any case – the camera was kept operating to see what would happen at this peculiar situation, and Zimbali has been a thrilling data-set to analyse both because of an exceptional diversity of prey remains, and this peculiar interaction between geese and eagles.

One would think that the eagles would simple dominate here, overpowering, even killing the geese right there on the nest site.  Recent Black Sparrowhawk research revealed that geese overpowered and usurped sparrowhawks, but the interaction between this particular eagle and goose duo has been somewhat of an example of commensalism.  In ecology, commensalism is a class of relationship between two organisms where one organism benefits without affecting the other- derived from the latin commensalis, meaning 'sharing a table'.

A summary of the situation – which I hope to describe in more detail on a journal note (so take heed of the copyright and intellectual property statement at the footer to the blog), is:

On the 28th of January, just a few days after the young N2 fledged, the goose first visits the nest and digs a goose-sized divot in the rotting nest lining. The first egg is laid on the 2nd of Feb and is subsequently kicked out - a full clutch of 7 eggs is laid by the 8th.

During the early stages of incubation the eggs are left covered and concealed for long periods while the eagles continued to deliver food, and the juvenile continued to eat casually on the nest. I am utterly shocked at how long these eggs can go without being brooded – and during data analysis held little hope for the success of this clutch of geese. Even up until the 10th of Feb N2 slept the night on the nest.  For the next few weeks the nest is shared between eagle feeding and geese brooding.

By the latter weeks in February the antagonism becomes clearer, maybe the geese eggs require far more attentiveness in order to ensure the survival of the duck embryos. So while the adult eagles still drop prey at the nest, it appears that the geese throw them out.  Zimbali visitors have had wonderful experiences with the trusting N2 while she had to eat her meals on the forest floor.

Floor food, a Blue Duiker leg. Photo by Benine Du Toit

The clutch of eggs were last seen on the evening 12th of March, and even on this day N2 had a nice feast of cane rat on the nest. By the morning of the 13th, the brooding behavior of the goose had noticeably changed – she now held her wings dropped – the eggs had probably hatched during the night, and the first glimpse of ducklings are seen shortly before 10am.  She keeps a very close watch over her brood and only leaves the nest once, very briefly, that evening.  The next morning, just 24 hours after hatching, its time to scarper before the little ducklings become eagle snacks.  At 6.42am the mother goose guides her little brood off the nest.  They jump and parachute 25 meters to the ground!

N2 received another meal from her parents at midday, and after eating her fill, she curiously crushed the hollow half-shells left in the nest.  Another month of camera monitoring until the 8th of April revealed no further trace of a goosey interest. N2 continued to receive meals, and consume them in peace on the nest.  The most recent photos were taken of a happy and healthy 'Miss Zimbali' on the 26th of May, and so it seems, life goes on!

Miss Zimbali as she is affectionately known by Adele Kieser (photographer)

Photo by Adele Kieser

Sample Size = 5

After another long delay I’ve got around to another research blog update. It has taken a while to make some good news. As of yesterday I had the fifth nest camera installed and operating.  It remains to be seen then, whether they are collecting full and complete data, when I service them in a fortnight’s time.

The delivery of four brand new, off the factory line, cameras came with complimentary software glitches. The glitch was somewhere between, not tolerating 32GB SD cards while operating on Timee Lapse in the glory of daylight.  It has taken three weeks to get a workable patch-up, and the cameras will need to be serviced more frequently than the older more stable cameras.  They tell me they have their software programmers working hastily on the next updates.

The fifth camera went up yesterday. The accommodating canopy of this big pine provided the best opportunity yet to have both Mia and I up working together on a camera.  And of course we had to have the classic i-was-here portraits!  A fantastic last day before heading back to Denmark for her work,  travel well Mia.

a camera int he paradise valley area

and at Zimbali Coastal Estate

Between delays in securing permits and the camera faults I have missed two to five weeks of young eaglet meals at these nests.  But these four are now up and running.  The Giba gorge camera is still up and has now recorded long series of a vacant nest.  The eaglet fledged sometime last week.  The camera remains in place because this youngster will still return to the nest for meals for many weeks to come. 

our E6 is the white speck on the dead branches on the far right, the nest down at the bottom left

September 2012 - progress

The Springtastc blog post uploaded on the 16th September was introducing a warming and wetting of the landscape, frogging weather and the expectation of snake weather.  Just three days later, and I see my first South African snake.   This amazing Rock Python, which must have been at least 2.5 meters long, slides across a gravel track out in the Mount Moreland sugarcane fields.  It stretched right across the road and was casually heading into the scrub when it must’ve got a whiff of me.  It turned and bolted across the road from where it had come from.  Those beasts can move quickly when they want to!

This was the day before Mia flew in from Denmark.  And after collecting her from King Shaka Airport late on Wednesday afternoon we rushed around to the Mount Moreland nest.  As dusk quickly drew the curtain of darkness, a surreal silhouette of the incubating Crowned Eagle sat atop the nest.  Twilight offered us plenty of bats as they flittered above the river, Fiery-necked Nightjars called, and while watching a Spotted Eagle Owl on the roadside down the car beams, a Large Spotted Genet saunters across the road.  Ever since I’ve known her Mia is has been some sort of magnet for wildlife spectacles, starting of course with one of our first days together out in Mongolia, where suddenly three wolves appeared, apparently abandoning an ambush on gazelles. 

I now have my partner here…  feeling a little humbled because my ‘field appy’ put me to shame on the first day by telling me which of the pair on this nest was the male and which was the female -followed shortly after by confirmation that the male can indeed do a little incubation, much doubted by me in the past.  Over the next ten days we will get stuck in to surveying the Durban nests, attempting to catch remaining 2011 juveniles, and maybe time to put up another camera or two.

The male stands cautiously over the nest while she watches closely.  She went off to fetch a leafy twig while he incubated for five minutes.  A powerful wind yesterday morning broke that stem, we hope the eggs are ok.

The female eagle at Victoria Country Club is unfazed by our observations.

Just recently Zimbali Estate has confirmed that they will sponsor a camera diet study on their nest.  Awesome – thanks ZEMA!

Finally, I'd like to do send you off to check out a couple of other Crowned Eagle blogs.  
A nest that is currently active and should provide fantastic entertainment this season 
http://crownedeaglediary.blogspot.com/
And the other, a few amazing photos from one of the 2011 breeding nests.
http://www.nightbirds.co.za/photos.html