|Falco peregrinus minor|
Distribution and abundance
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The resident African race Falco peregrinus minor of this cosmopolitan species is widespread but scarce throughout its range from Morocco in the n to the s Cape coast (del Hoyo et al. 1994). The known southern African population is c 850 prs with about 300 prs in Zimbabwe (Hartley 2000), c 400 prs in South Africa (Jenkins & Barnes 2000), and c 150 prs in Botswana and Namibia (A Jenkins pers comm.). In Namibia it is thinly spread across the entire country but some of those recorded were probably the migratory calidus subspecies (Jenkins 1997). There is a tendency for African Peregrines to occur mainly in the western regions where montane breeding habitat is more common, and along the two desert rivers - the Orange and Cunene (Jenkins 1997).
The Namibian population has not been assessed, but breeding prs are found around the Waterberg Plateau Park (3-14 prs: Brown & Cooper 1987, Simmons 2002), along the cliffs of the Orange River (8-12 prs: Jenkins & Barnes 2000), the Cunene River (1 pr in 11 km: RE Simmons unpubl data) and 1 pr in the dry Ugab River (Braby et al. 1987). One nest site is known from the Erongo Mountains and suitable cliffs occur on the w escarpment of the same range (RE Simmons, PE Barnard pers obs). One pr is known to inhabit the Swakop River gorges and others probably occur in the Kuiseb River canyon (R Braby pers obs). Birds and presumably breeding prs are recorded from the Fish River and the ephemeral rivers of the Skeleton coast (Jenkins 1997) where suitable cliffs exist for breeding prs (Braby et al. 1987, J Paterson pers comm). From these surveys it is estimated that 70 - 100 prs of Peregrines occur in Namibia.
Its area of occupancy in Namibia is 52,466 km2 (Jarvis et al. 2001), the mean reporting rate across the range was 2.6% (Jenkins 1997), and the number of birds seen in Namibian raptor road counts was 0.34 birds/1,000 km (Jarvis et al. 2001).
The resident African species prefers any areas where sheer cliff-habitat occurs, particularly where it overlooks suitable bird habitat such as woodlands or wetlands (Hustler 1983, Jenkins 1994). Vegetation types are relatively unimportant if suitable cliffs are available (Jenkins 1997), and the linear oasis effect of desert rivers may be sufficient to concentrate bird prey (Braby et al. 1987, Simmons & Allan 2002). Feeds exclusively on birds, especially medium-sized birds such as pigeons and doves, but will also tackle (unsuccessfully) larger species (up to size of Lesser Flamingo) and regularly takes smaller species than doves (Jenkins & Avery 1999).
Breeds mainly in the spring (August-December) with a tendency for later breeding at higher latitudes (Jenkins 1997). Breeding records from Namibia are sparse but egg-laying has been recorded in August (1), September (5) and October (1) (Brown & Clinning unpubl data) with broods of 2, 2 and 3 young (Jarvis et al. 2001). Along the Orange River the mean laying date was 10 September, with a range 28 August - 4 October. An average of 1.7 young per pair were fledged from 8 prs over 47 pr yrs (Jenkins 2000). Warm spring weather appears to promote greater fledging success in mesic environments (Jenkins 2000), but this may not occur in the more arid Namibian environment.
There are few threats to this species in Namibian given its relatively remote breeding cliffs. However, pesticides such as Dieldrin and DDT are regularly used in Namibia for the control of malaria and Tsetse Fly (Brown & Kock unpublished data), and these may find their way into the environment. This is not likely to effect west-coast Peregrines because there is little pesticide use there. In cases where soil temperatures are high the likelihood that evaporation will reduce levels of DDT or DDE in the food chain are also high (Brown & Kock unpublished data). However, DDT and other lethal chemicals are clearly contaminating food chains in southern Africa and entering the raptor community because thinner eggs and dead birds still occur in cooler climates (Curtis & Jenkins 2001). If malaria becomes more prevalent under warmer climate change scenarios (Rogers & Randolph 2000), then pesticide usage is likely to increase and may influence highly sensitive bird-eating raptors such as Peregrines in central regions or along rivers. The use of pesticides along the Orange River and other dead raptors there (Simmons & Allan 2002) suggest Peregrines breeding there may be at risk. Elsewhere collision with transmission lines and fences have caused injuries and fatalities in South Africa (A Jenkins unpubl data), and this requires monitoring in Namibia.
This species is classified as Near-Threatened because of apparent but difficult to interpret declines in the Waterberg Plateau Park region: 14 pairs were recorded there in helicopter surveys in 1984 (Brown & Cooper 1987) but only 6 birds (1 definite pr) representing at most 3 prs were recorded 16 yr later (Simmons 2002). Birds nesting in the Ugab River (Braby et al. 1987) were not subsequently reported by the same observers, despite regular patrols in the area. Birds are also scarce in montane regions such as the Erongo Mountains where many more pairs should occur. These may reflect fluctuations arising from wetter and drier years as bird-prey become more or less plentiful, but it may also represent a real decline. Peregrine Falcons are not listed as globally threatened following their recovery from the DDT era in North America and Europe (Stattersfield & Capper 2000). However, is categorised as Near-Threatened in South Africa because numbers are relatively low and pesticide uptake requires monitoring in all populations where DDT is still applied (Jenkins & Barnes 2000).
Monitoring of known populations such as the Waterberg Plateau Park where baseline studies provide the basis for time-series assessments should be carried out regularly. These could be undertaken concurrently with surveys of other threatened species such as Cape Vultures and Black Eagles (Brown & Cooper 1987, Simmons 2002). Other regions where peregrines are regular such as the Cunene River should be monitored for breeding population and breeding success, and compared with that from the probably contaminated Orange River population (Jenkins 2000). Investigation of egg shell thickness at nests where egg shells can be collected will be useful to compare with populations where declines are known to have taken place. Unhatched eggs should be investigated for contamination, and surveys in accessible mountains may reveal more pairs than currently estimated.
From: Simmons RE & Brown CJ 2006. Birds to watch in Namibia: red, rare and endemic species. National Biodiversity Programme, Windhoek, Namibia
Barnes KN (ed) 2000. The Eskom Red data book of birds of South Africa, Lesotho and Swaziland.
Braby, Rod Personal observation from the central Namibian rivers. Chief Control Warden Erongo Region, (firstname.lastname@example.org).
Braby R, Paterson J & Brown CJ 1987. Peregrine Falcon breeding in the Namib Desert. Gabar 2: 43-44.
Brown CJ, Kock A Unpublished data. DDT in an arid environment.
Brown CJ, Cooper TG 1987. The status of cliff-nesting raptors on the Waterberg, SWA/ Namibia. Madoqua 15: 243-249.
Curtis O Jenkins AR 2001. It's never too late to learn: The effects of pesticides on southern African environments. African Wildlife 55: 13-15.
Curtis OE, Jenkins AR 2002. Shell thickness and size of Peregrine Falcon Falco peregrinus minor eggs from two areas in South Africa. Ostrich 73:64-66.
Hartley RR 2000. Ecology of Taita Falco fasciinucha, Peregrine F. peregrinus minor and Lanner F. biarmicus Falcons in Zimbabwe. In Chancellor RD & Meyburg B-U (Eds). Raptors at risk. Pp 87-105 WWGBP/Hancock House, British Columbia, Canada.
Hustler K1983 The breeding biology of the Peregrine Falcon in Zimbabwe. Ostrich 54: 161-171.
Jarvis A, Robertson AJ, Brown CJ, Simmons RE 2001. Namibian Avifaunal Database. National Biodiversity Programme, Ministry of Environment & Tourism, Windhoek.
Jenkins AR 1994. The influence of habitat on the distribution and abundance of Peregrine and Lanner Falcons in South Africa. Ostrich 65: 281-290.
Jenkins AR 1997 Peregrine Falcon. In: Harrison JA, Allan DG, Underhill LG, Herremans M, Tree AJ, Parker V, Brown CJ (eds). The Atlas of Southern African Birds. Vol. 1: 250-251. BirdLife South Africa, Johannesburg.
Jenkins AR 2000. Factors affecting breeding success of Peregrine and Lanner Falcons in South Africa. Ostrich 71: 385-392.
Jenkins AR, Avery GM 1999. Diets of breeding Peregrine and Lanner Falcons in South Africa. J Raptor Res 33: 190-206.
Jenkins AR, Barnes KN 2000 Peregrine Falcon In : Barnes KN (ed). The Eskom Red data book of birds of South Africa, Lesotho and Swaziland. Pp140-141. Birdlife South Africa, Johannesburg.
Paterson, John personal observation. Control Warden, Skeleton Coast Park (email@example.com)
Rogers DJ, Randolph SE 2000. The global spread of Malaria in a future warmer world. Science 289: 1763-1766.
Simmons RE 2002. A helicopter survey of Cape Vultures Gyps coprotheres, Black Eagles Aquila verreaxii and other cliff-nesting birds of the Waterberg Plateau, Namibia, 2001. Vulture News 46: 3-7.
Simmons RE, Allan DG 2002. The Orange River avifauna: abundance, richness and comparisons Ostrich 73: 92-99.
Simmons Rob, Barnard Phoebe, Personal observations from the Erongo Mountains (firstname.lastname@example.org).
Stattersfield AJ, Capper DR (eds) 2000 Threatened Birds of the World. Birdlife International, Cambridge. UK.