It can take a while after putting out the marrow bones on the nearby rocks for the big birds to arrive. But when they do, it is a thrilling sight as they glide by soundlessly before swooping down to collect a bone, which they will later release from on high to smash against a rock, allowing them to get to the marrow.
These are the bearded vultures of the Drakensberg, and the setting is the Giant's Castle Nature Reserve bird-viewing hide on a high hill overlooking a valley with the towering mountain range's green slopes and imposing cliffs on the far side.
The bones are provided by the reserve management to allow birders to get a close look at the vultures.
The site may offer one of the most thrilling bird-watching experiences, but it is just one of a rich array of scenic spots that constitute the Southern KwaZulu-Natal Birding Route.
Having just been opened, it offers birders, as in fact all ecotourists, some of the most rewarding wildlife experiences to be had in Southern Africa.
As aptly described by Dr Morne du Plessis, the chief executive of the Worldwide Fund for Nature, one of the route's sponsoring bodies, "the landscape offers a diversity of biological wonders compressed into a relatively small area, from the peaks and forested mountain ravines of the Drakensberg, to rolling grasslands and mistbelt forests through to riverine, coastal and estuarine regions within a single day".
"And on a north-south axis, one can cross from valley bushveld, mangrove forests and dune forests all the way into thornveld savanna habitats," Du Plessis enthuses.
This extraordinary range of habitats makes it home to more than half of South Africa's close to 900 bird species.
Among these are many endemics and rarities such as the blue swallow, Cape parrot and Drakensberg rock-jumper. And as if to demonstrate their valued presence, crowned cranes feeding on a harvested cropland in the Karkloof area near Howick entertained the media and dignitaries who attended the birding route's opening ceremonies with their quaint dance routine.
Bird routes have a dual purpose. They promote tourism by helping to guide wildlife tourists to a region's most attractive nature spots.
They also generate tourism and the hospitality industry, and create jobs, such as for trained bird guides, and they encourage conservation by co-opting local communities and farmers into looking after precious habitats.
Sappi pulp and paper company, one of the country's largest land owners whose activities happen to have a major impact on the natural environment, is a leading commercial partner of the bird-route programme.
The company's head of corporate affairs, André Oberholzer, expressed confidence at the birding route's opening that it would be of great benefit to the region's communities.
Other partners of the programme are BirdLife South Africa, which, in turn, is a member of the powerful BirdLife International coalition of environmental organisations in more than a hundred countries, and the Wildlands Conservation Trust, a KwaZulu-Natal-based environmental organisation that strives to conserve biodiversity through socio-economic development projects. The birding route has four components, each of which comprises a range of remarkable features.
The Midlands section stretches from the Ukhahlamba-Drakensberg World Heritage Site, with its Giant's Castle vulture hide, down to the rolling hills of the KwaZulu-Natal Midlands. It includes the picturesque Karkloof, where an information centre has been opened for visitors where they can arrange for bird guides and entry to properties.
The Sisonke route reaches seaward from the southerly part of the Drakensberg, including Sani Pass, and takes in the new Marutswa Forest Boardwalk on the outskirts of the pretty mountain village of Bulwer.
The Ethekwini section includes the array of forest, wetland, bush and grassland parks in and around Durban, and the South Coast route takes in the lush landscape along the coast.