HOME ON THE R A NGE Raptor riches of the

The juxtaposition of wilderness and the urban environment is extreme on South ’s Cape Peninsula, where more than three million people live sandwiched between the Table Mountain massif and the open Atlantic Ocean. Although justifiably world famous for its beautiful and diverse flora, the Peninsula is not renowned for its avifauna. It does, however, support healthy populations of many of the region’s endemic and, perhaps most remarkably, it is home to an amazing array of of prey. At least 13 raptor species are present as breeding residents on the Cape Peninsula and a further five occur as regular visitors or migrants. These birds live, largely unnoticed, in and around the urban fringes, as well as in the wilder, more remote reach- es of the Peninsula. They represent a previously unrecognised, but highly significant, component of the region’s natural heritage and they are integral to the uniquely diverse and accessible nature experience that awaits visitors to the area. With the establishment of the Cape Peninsula National Park CPNP( ) and ongoing associated changes in local environmental management, now is an opportune time to focus some attention on the Peninsula’s raptors, document their present conservation status, and discuss ways of ensuring their continued survival.

Peregrines defend their cliffs aggressively against TEXT BY ANDREW JENKINS & ANTHONY VAN ZYL all-comers. This female was photographed during a visit to her nest to measure and ring her chicks. PHOTOGRAPHS BY ANDREW JENKINS Tygerberg Durbanville Hills Signal Hill Bellville CAPE TOWN Table ATLANTIC Mountain OCEAN CAPE PENINSULA NATIONAL PARK

CAPE FLATS Hout Bay

Silvermine Nature Reserve FALSE BAY Kommetjie Fish Hoek CAPE PENINSULA NATIONAL PARK Simon’s Town

Scarborough

Cape of Good Hope Nature Reserve

Cape Point

Above The Cape Peninsula and environs, Mountain sentinels which are potentially suitable for cliff- The Black or Verreaux’s Aquila an area of about 1 400 square kilometres, The many cliff-nesting raptors that course nesting birds. But the available habitat verreauxii population of the Peninsula is supports about 100 pairs of cliff-nesting along the great sandstone scarps of Table doesn’t stop here. Some cliff-nesters fail noticeably depleted. Even comparatively raptors and ravens. Mountain and the Peninsula mountain to differentiate between natural cliffs and recent historical accounts suggest that chain, and perch on the rocky ramparts analogous, man-made structures such as these magnificent birds were fairly com- Opposite above The Black Eagle was that overlook the city and the sea, are quarry faces or even multi-storey build- mon in the area, but this is no longer the previously more widespread on the probably the most prolific and conspicu- ings. On the Peninsula, most tall or case. A number of huge stick-nests that Cape Peninsula than it is today. ous of the Peninsula’s birds of prey. prominent buildings around the urban could only have been built by this species As scientists researching two such cliff- centres are attractive to peregrines, just still adorn the cliffs of the Peninsula and Opposite below An adult Black Eagle nesting species, the Peregrine Falcon Falco about any elevated structure seems suited bear testimony to a once more substantial tending a chick at a new nest in the peregrinus and the Rock Kestrel F. tinnun- to kestrel pairs, and disused stone quarries population. While these structures now Tygerberg Hills could be a sign of better culus, we were initially drawn to the Cape have proved popular with all the cliff- lie unattended, their distribution suggests things to come… Peninsula as a study area because of its nesting species. This behavioural plasticity that perhaps as many as seven or eight proximity to our research base, the Fitz- has enabled these birds, and peregrines pairs of these formerly graced the Patrick Institute at the University of Cape and kestrels in particular, to move away mountain chain. Now only one pair is Town. We started monitoring and observ- from the mountain range and colonise resident along the western reaches of ing falcon and kestrel pairs in the late the Cape Flats and coastal plain to the Table Mountain, with a second territory 1980s and since then have conducted north of the city. active occasionally on the Karbonkelberg annual surveys of most of the available range near Hout Bay, and a new site habitat for these birds, incidentally accu- Raptor populations and ravens recently established in a quarry to the mulating a reasonable knowledge of the We estimate that the Peninsula is current- north of the city. There is no obvious populations of the other montane raptors ly home to about 100 breeding pairs of reason for this decrease in the eagle pop- present in the area. We’ve been increasing- cliff-nesting raptors and ravens. Of this ulation, although habitat loss and the ly impressed, generally encouraged, but total, about 75 pairs are resident within concomitant decline in prey availability occasionally concerned by our findings. the boundaries of the CPNP, with the may be implicated. Black Eagles are most remainder occurring in variously modi- easily seen from the upper station of the Raptor country fied environments within and around the Table Mountain Aerial Cableway, and There are nearly 200 sheer rockfaces on perimeter of the city. Five species are pre- the Table Mountain pair often soar high the Cape Peninsula, totalling more than sent as regular breeders: the Black Eagle, over the Cape Town CBD. 40 kilometres of cliffs along the mountain Jackal , Peregrine Falcon, Rock Jackal rufofuscus proved chain from Signal Hill to Cape Point, all of Kestrel and White-necked Raven. elusive on the Peninsula, and we found

40 CAPE PENINSULA RAPTORS AFRICA – BIRDS & BIRDING OCTOBER/NOVEMBER 2002 CAPE PENINSULA RAPTORS41 Above The diagnostic underwing only three active nests during the survey easily seen hanging in the wind-sheer pattern of the Jackal Buzzard shows period. However, repeated sightings of along the ridges of the south-east coast of to good effect as the hangs in adult birds in the same areas at the right the Peninsula, between Simon’s Town a mountain updraft. time of year, with observations of copula- and Cape Point. tion and food-carrying, suggested a num- We probably secured the most reliable Opposite A Peregrine Falcon scans ber of other breeding pairs. On this basis, population estimate for peregrines, with the False Bay coastline for hunting we identified seven ‘good’ Jackal Buzzard 23 known territories and possibly a couple opportunities. territories, including two nests in trees of additional sites yet to be found. The 16 adjacent to quarries. We could easily have pairs resident in the CPNP area constitute missed a couple of cliff sites, so we set our one of the highest breeding densities of estimate at about 10 pairs for the moun- peregrines in Africa, and the most sub- tain chain. There are doubtless other tree- stantial conserved population of this Red nesting pairs, particularly in areas where Data species in . stands of large exotic trees provide ample Peregrines hunt other birds in spectacu- nesting opportunities. lar aerial strikes, and generally require a Generally, Jackal Buzzards are surpris- height advantage over their prospective ingly uncommon in the area, and are prey from which to descend at extreme most frequent in the remote, southern speeds in a near-vertical dive or stoop. reaches of the CPNP – in the old Silver- While they often initiate hunts from the mine and Cape of Good Hope nature air, perch-hunting is more energetically reserves – that feature tall expanses of efficient, so high cliffs (and other vantage broken, grey sandstone. As a southern points) with an unobstructed view over African endemic, the strikingly-coloured suitable hunting terrain are at a premium Jackal Buzzard is a drawcard for raptor- in any peregrine territory, and pairs on philes and twitchers alike, and is most the Peninsula dominate all the taller,

42 CAPE PENINSULA RAPTORS AFRICA – BIRDS & BIRDING Ravens Corvus albicollis in our surveys as ‘honorary raptors’. However, despite ap- pearances, they function very much as passerines, and initially we found much of their behaviour difficult to fathom. They are very active for such large birds, and pairs are always busy doing something indiscernible (possibly foraging?), that we have called ‘raven stuff’. We also found their breeding biology confusing, in par- ticular their tendency to completely relo- cate to different or new nests within their respective territories each season, and the disconcerting speed with which they pro- gressed from apparently preparing a nest for breeding to piling food into four well- developed youngsters! Despite these problems, we’ve devel- oped a pretty solid estimate of raven num- bers on the Peninsula. We know of 19 ‘nesting areas’ and, allowing for some omissions, estimate the total population at a maximum of 25 pairs. Most occupy smallish, overhung cliffs within the CPNP area. Ravens typically build their nests in very sheltered situations, and their dis- used nests are often taken over by breed- ing peregrines. Above Peregrines thrive in urban more imposing rockfaces. The notorious point, where a pair regularly hunts from Ravens can be seen foraging and centres around Cape Town. This bird Cape weather also strongly influences nest- the communications mast just north of patrolling in pairs or family groups in has been colour-ringed as part of a site selection. We found that breeding pairs the old lighthouse. most parts of the CPNP. They are diligent demographic study. prefer overhung cliffs, even quite low crags, The Rock Kestrel is the most numerous scavengers of human refuse, and the that are sheltered from the fierce gales that of the mountain’s ‘Big Five’. We recorded upper cable station on Table Mountain or Below A large, sheltered nest ledge sweep the Peninsula. They are prone to 35 active territories, but the actual popula- any of the more popular picnic spots protects a brood of peregrine chicks breeding failure at exposed nest ledges or in tion probably exceeds 50 pairs in good along the coastal roads are probably the from the cold-front systems that years with unusually cold, wet spring weather. years, and is definitely prone to annual best places to see them. they come into conflict with human Top Rock Kestrel chicks in an old crow characterise the Cape. Peregrines can be seen virtually any- fluctuations, presumably in response to interests. For example, circumstantial evi- nest under the eaves of a building. where on the Peninsula, but perhaps changes in weather and food availability. Urban hazards dence suggests that moderate losses of most easily at the main Cape Point view- Given this species’ sensitivity to local con- Unfortunately, pressure from the bur- homing or racing pigeons to peregrines Above The Rock Kestrel is one of the ditions, we struggled to monitor known geoning human population on the natur- and other bird-eating raptors (such as most commonly seen small raptors on territories each year, and locating new al areas of the Peninsula has increased Black Sparrowhawk Accipiter melanoleucus) the Cape Peninsula. nests of this small species in complex, exponentially in the past 10–20 years. have been sufficient to spark a low-key built-up environments and in the vast Housing and commercial developments campaign among pigeon-fanciers to shoot expanses of rock available in the higher now cover almost all the flatter, more or poison these birds. Without proper regu- northern reaches of the mountain chain accessible land, and are rapidly encroach- lation and management, this problem is proved very difficult. ing on the mountain chain itself. Even for set to escalate. Rock Kestrels are ubiquitous on the the die-hard, city-slicking falcon or The negative effects of habitat loss and Peninsula, but they are particularly abun- kestrel, the urban environment is fraught environmental pollution on cliff-nesting dant in the northern suburbs, and the with hazards. raptors are less obvious but probably no quarries around Durbanville are probably The more obvious negative effects of less important. For example, eagle, buz- the best places to see this species in the development are those that directly cause zard and kestrel densities are almost Cape Town area. Other good stake-outs mortality. For example, raptors flying at certainly negatively affected by the loss are the western slopes of Lion’s Head, or speed in built-up areas run the risk of col- of foraging habitat associated with the else the small cliff-line that runs above the liding with overhead lines (electricity simultaneous spread of development and road heading south from Kommetjie cables, telephone lines), vehicles and alien vegetation, and the accumulation of towards Scarborough. buildings. At least 70 per cent of ringed agrochemicals and industrial toxins in As they are large, soaring birds that peregrines recovered on the Peninsula sus- the bodies of urban peregrines and nest on cliffs and generally hold exclusive tain injuries or are killed in such colli- kestrels probably compromises all aspects territories, we included White-necked sions. Also, raptors may be persecuted if of their biology.

44 CAPE PENINSULA RAPTORS AFRICA – BIRDS & BIRDING OCTOBER/NOVEMBER 2002 CAPE PENINSULA RAPTORS45 Disturbance is another telling factor. along the mountain chain (and in the More and more people use the CPNP each forests, flats and wetlands), to species- year, and leisure activities such as rock- specific viewing and information sites, or climbing and paragliding are progressively even hides overlooking nesting areas. invading the sheer rockfaces and open air- We’re also considering various exciting space which until recently were exclusive- high-tech options, such as closed-circuit ly the domain of the mountain’s birds. TV cameras or webcams positioned at These activities can cause damaging levels nests which will transmit live images of of disturbance at active nests. Thankfully, breeding birds to CCTV screens or an a combination of effective control by the Internet website. With luck, opportunities managing authorities and co-operation for commercial exposure on signage and from sports bodies and participants can in multi-media coverage will be sufficient substantially alleviate such problems. For to attract a corporate sponsor to fund the example, in the past few years, climbing route and its associated research and con- routes through sensitive areas of the CPNP servation costs. have been temporarily closed, with very The route should also serve to raise the promising results. profile of the Peninsula’s raptors in future management plans for the area, and Routing for raptors stimulate concern for the welfare of these We hope to secure the future of the impressive birds. Charismatic eagles, We would like to thank Steve Phelps Peninsula’s raptors by developing a ‘Cape hawks and falcons have considerable of Peregrine Properties (Pty) Ltd, Peninsula Raptor Route’. This self-guided potential as vehicles for conveying the Mvelaphanda Property Holding Com- tourist route will comprise about 10 loca- basic principles of conservation. Perhaps pany (Pty) Ltd and the Cape Bird Club tions between the Tygerberg Hills and by instilling a genuine appreciation of the for partly sponsoring our research. Cape Point that showcase the area’s rap- aesthetic value and ecological significance tors. Locations will vary in nature from of our birds of prey, we can contribute to general information signboards, posi- a greater awareness of broader environ- A White-necked Raven stands sentinel tioned at nodes of tourist activity and mental issues, and truly keep these mag- over the Cape Flats. describing the raptor species that occur nificent birds at home on the range.

46 CAPE PENINSULA RAPTORS AFRICA – BIRDS & BIRDING