| Lesser Kestrel | |
| Falco naumanni | |
| Status: | Near-Threatened |
Distribution and abundance
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This species is a migrant to southern Africa, where possibly most of the Eurasian population spend the non-breeding season from October to April (Siegfried & Skead 1971, McCann 1997). In southern Africa the core population occurs in the Free State, n Eastern Cape and North West Provinces of South Africa but it is distributed sparsely across Botswana, Namibia and Zimbabwe (McCann 1997).
In Namibia it is found in very thinly across central farmland with an area of occupancy of 52,199 km2 (Jarvis et al. 2001), and a reporting rate that averages 4.8% (McCann 1997, Jarvis et al. 2001). The global population is presently estimated at 100,000 birds (Pepler 2000), down from 154,000 birds estimated from roost surveys in South Africa in the early 1980s (Pepler 2000). The southern African population is now estimated at 50,000 - 60,000 birds (Pepler 2000, Birdlife International 2004) of which the majority occur in South Africa. Elsewhere populations are reported to have declined more than 50% (del Hoyo et al. 1994, Biber 1996). The Namibian population is unlikely to be more than 1,000 birds judging by the very low reporting rates and the area occupied during summer months. This represents < 2% of the southern African population. At least some Namibian birds migrate from eastern Russia, given that a juvenile was recovered (shot) at Windhoek International Airport supporting a Russian ring from 8,000 km away (Oatley et al. 1998).
Ecology
Prefers the Grassy Karoo habitat in South Africa where reporting rate is 22% (McCann 1997), but is also found over farmland or other short vegetation types in drier regions. In these areas massive roosts can form, some of which have been monitored for over 30 years - often in the same tall eucalyptus trees (Pepler 2000). These tall trees are often linked with human habitation and are always alien species suggesting a dependence on human-altered landscapes In southern Africa it feeds on Arthropods such as solifugids and orthoptera (Anderson et al. 1999), often in dense flocks by hovering and perch hunting (Zank & Kemp 1996). It feeds on locust swarms and birds appear to follow locust outbreaks but not similar sunspider (solifuge) population highs (Kopij 2002). Breeding is extralimital and no mass roosting sites are known from Namibia, but they might be expected given the social nature of this kestrel.
Threats
Most threats to this species occur in its breeding grounds of Eurasia where breeding habitat and foraging habitat has been lost to agricultural intensification in its grassland-steppe habitat (Biber 1996). However, agriculture has also transformed large proportions of grassland used as foraging areas in South Africa. Kestrels continue to hunt over such habitat, but are often attracted to population outbreaks of locusts or crickets which are subsequently sprayed with persistent agrochemicals by farmers (Pepler 2000). The overall effect on populations appears not to have been documented in southern Africa. Roost trees are sometimes removed because of the noise associated with roosts and feaces that collect beneath such trees from the constant use by thousands of birds (Pepler 2000). Mortality of over 350 birds has also been recorded from hail storms that hit roosting birds in alien (gum) trees that afford the kestrels little protection (Taljaard & Anderson 1994). Birds foraging over the short grass at airports are sometimes shot because they are a potential risk to aircraft (Anderson et al. 1999), and this has occurred in Namibia too (Oatley et al. 1998).
Conservation status
This subspecies is given Near-Threatened status here because it is classified elsewhere as globally threatened but is not threatened per se in Namibia. Neither is Namibia a core area for migrant birds. It has undergone a 46% decline every 10 years since 1950 in Europe, and 25% decline every 10 years since 1971 in South Africa qualifying it for Vulnerable both globally (Birdlife International 2004) and in South Africa (Pepler 2000).
Actions
Surveys for Lesser Kestrels in Namibian grasslands should be undertaken and any roost sites catalogued and monitored for the number of roosting birds from November - March. All such records should be contributed to the ongoing Migrating Kestrel project (see www.kestreling.com). Significant roosting or foraging sites should be monitored for pesticide spraying or habitat alteration and landowners alerted to the importance of their land for this species. Any regular roosting sites should be protected and any dead birds examined for rings and analysed for pesticides. Shooting this globally threatened species at airports anywhere in southern Africa should be prevented by alerting airport authorities to the threatened status of the species and possibly using other methods to prevent birds hunting there. Ridding short grass areas at airports of insects shortly after the rains may pre-empt Lesser Kestrels and other insect-eating species from congregating in such areas.
From: Simmons RE & Brown CJ 2006. Birds to watch in Namibia: red, rare and endemic species. National Biodiversity Programme, Windhoek, Namibia
References
Anderson PC, Kok OB, Erasmus BH 1999. Diet, body mass and condition of Lesser Kestrels Falco naumanni in South Africa. Ostrich 70: 112-116.
Biber J-P 1996. International Action Plan for the Lesser Kestrel Falco naumanni In: Heredia B, Rose L, Painter M (eds) Globally threatened birds in Europe: action plans. Pp 191-203. Birdlife International, Strasbourg.
Birdlife International 2004 Threatened Birds of the World. Birdlife International, Cambridge.
Del Hoyo J, Elliot A, Sargatal J (eds) 1994 Handbook of the Birds of World Vol 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona.
Jarvis A, Robertson AJ, Brown CJ, Simmons RE 2001. Namibian Avifaunal Database. National Biodiversity Programme, Ministry of Environment & Tourism, Windhoek.
Kopij G 2002 Food of the Lesser Kestrel (Falco naumanni) in its winter quarters in South Africa J of Raptor Research 36: 148-152.
McCann K 1997. Lesser Kestrel Falco naumanni In: Harrison JA, Allan DG, Underhill LG, Herremans M, Tree AJ, Parker V, Brown CJ (eds). The Atlas of Southern African Birds. Vol. 1: 268-269 BirdLife South Africa, Johannesburg.
Oatley TB, Oschadleus HD, Navarro RA, Underhill LG 1998 Review of ring recoveries of birds of prey in southern Africa: 1948-1998. Avian Demography Unit, Univ Cape Town.
Pepler D 2000. Lesser Kestrel Falco naumanni In: Barnes KN (ed). The Eskom Red data book of birds of South Africa, Lesotho and Swaziland. Pp 90-92. Birdlife South Africa, Johannesburg.
Siegfried WR, Skead DM 1971. The status of the Lesser Kestrels in South Africa. Ostrich 42:1-4.
Taljaard FD, Anderson MD 1994. Violent hailstorm kills 357 Lesser Kestrels. Gabar 9: 28-29.
Zank CM, Kemp AC 1996. A comparison of hunting behaviour by Lesser Kestrels Falco naumanni and Eastern Redfooted Falcons Falco amurensis in their non-breeding South African range. Ostrich 67: 63-66.