Home on the Range 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. 

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

40 cape peninsula raptors africa – birds & birding october/november 2002 cape peninsula raptors 41 Above The diagnostic underwing proved elusive on the Peninsula, and we philes and twitchers alike, and is most pattern of the Jackal Buzzard shows found only three active nests during the easily seen hanging in the wind-sheer to good effect as the hangs in survey period. However, repeated sight- along the ridges of the south-east coast of a mountain updraft. ings of adult birds in the same areas at the the Peninsula, between Simon’s Town right time of year, with observations of and Cape Point. Opposite A Peregrine Falcon scans copulation and food-carrying, suggested a We probably secured the most reliable the False Bay coastline for hunting number of other breeding pairs. On this population estimate for peregrines, with opportunities. basis, we identified seven ‘good’ Jackal 23 known territories and possibly a couple Buzzard territories, including two nests in of additional sites yet to be found. The 16 trees adjacent to quarries. We could easily pairs resident in the CPNP area constitute have missed a couple of cliff sites, so we one of the highest breeding densities of set our estimate at about 10 pairs for the peregrines in Africa, and the most sub- mountain chain. There are doubtless stantial conserved population of this Red other tree-nesting pairs, particularly in Data species in . areas where stands of large exotic trees Peregrines hunt other birds in spectacu- provide ample 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 

42 cape peninsula raptors africa – birds & birding Ravens Corvus albicollis in our surveys as ‘honorary raptors’. However, despite appear­ ances,­ 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 some- thing indiscernible (possibly foraging?), that we have called ‘raven stuff’. We also found their breeding biology confusing, in particular their tendency to completely relocate to different or new nests within their respective territories each season, and the disconcerting speed with which they progressed from apparently prepar- ing 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 numbers 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 the Peninsula dominate all the taller, more most easily at the main Cape Point view- Ravens can be seen foraging and patrol- centres around Cape Town. This bird imposing rockfaces. The notorious Cape point, where a pair regularly hunts from ling in pairs or family groups in most has been colour-ringed as part of a weather also strongly influences­ nest-site the communications mast just north of parts of the CPNP. They are diligent scav- demographic study. selection. We found that breeding pairs pre- the old lighthouse. engers of human refuse, and the upper fer overhung cliffs, even quite low crags, that The Rock Kestrel is the most numerous cable station on Table Mountain or any of Below A large, sheltered nest ledge are sheltered from the fierce gales that sweep of the mountain’s ‘Big Five’. We recorded the more popular picnic spots along the protects a brood of peregrine chicks the Peninsula. They are prone to breeding­­­­­­­­­ 35 active territories, but the actual popu- coastal roads are probably the best places from the cold-front systems that failure at exposed nest ledges or in years with lation probably exceeds 50 pairs in good to see them. they come into conflict with human Top Rock Kestrel chicks in an old crow characterise the Cape. unusually cold, wet spring weather. years, and is definitely prone to annual interests. For example, circumstantial evi- nest under the eaves of a building. Peregrines can be seen virtually any- fluctuations, presumably in response to Urban hazards dence suggests that moderate losses of where on the Peninsula, but perhaps changes in weather and food availability. Unfortunately, pressure from the bur- homing or racing pigeons to peregrines Above The Rock Kestrel is one of the Given this species’ sensitivity to local con- geoning human population on the natu- and other bird-eating raptors (such as most commonly seen small raptors on ditions, we struggled to monitor known ral areas of the Peninsula has increased Black Sparrowhawk Accipiter melanoleucus) the Cape Peninsula. territories each year, and locating new exponentially in the past 10–20 years. have been sufficient to spark a low-key nests of this small species in complex, Housing and commercial developments campaign among pigeon-fanciers to shoot built-up environments and in the vast now cover almost all the flatter, more or poison these birds. Without proper expanses of rock available in the higher accessible land, and are rapidly encroach- regulation­­­­ and management, this prob- northern reaches of the mountain chain ing on the mountain chain itself. Even for lem is set to escalate. proved very difficult. the die-hard, city-slicking falcon or kes- The negative effects of habitat loss and Rock Kestrels are ubiquitous on the trel, the urban environment is fraught environmental pollution on cliff-nesting Peninsula, but they are particularly abun- with hazards. raptors are less obvious but probably no dant in the northern suburbs, and the The more obvious negative effects of less important. For example, eagle, buz- quarries around Durbanville are probably development are those that directly cause zard and kestrel densities are almost the best places to see this species in the mortality. For example, raptors flying at certainly­­ negatively affected by the loss Cape Town area. Other good stake-outs speed in built-up areas run the risk of col- of foraging habitat associated with the are the western slopes of Lion’s Head, or liding with overhead lines (electricity simultaneous spread of development and else the small cliff-line that runs above the cables, telephone lines), vehicles and alien vegetation, and the accumulation road heading south from Kommetjie buildings. At least 70 per cent of ringed of agrochemicals and industrial toxins in towards Scarborough. peregrines recovered on the Peninsula the bodies of urban peregrines and kes- As they are large, soaring birds that sustain injuries or are killed in such colli- trels probably compromises all aspects of nest on cliffs and generally hold exclusive sions. Also, raptors may be persecuted if their biology.  territories, we included White-necked

44 cape peninsula raptors africa – birds & birding october/november 2002 cape peninsula raptors 45 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 We’re also considering various exciting airspace which until recently were exclu- high-tech options, such as closed-circuit sively the domain of the mountain’s TV cameras or webcams positioned at birds. These activities can cause damaging nests which will transmit live images of levels of disturbance at active nests. breeding birds to CCTV screens or an Thankfully, a combination of effective Internet website. With luck, opportunities control by the managing authorities and for commercial exposure on signage and co-operation from sports bodies and par- in multi-media coverage will be sufficient ticipants can substantially alleviate such to attract a corporate sponsor to fund the problems. For example, in the past few route and its associated research and con- years, climbing routes through sensitive servation costs. areas of the CPNP have been temporarily The route should also serve to raise the closed, with very 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 for tions between the Tygerberg Hills and by instilling a genuine appreciation of the 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