620 Apodidae: swifts

Breeding: Egglaying takes place September– April in the Transvaal (Tarboton et al. 1987b) and September–May with a November peak in Zim- babwe (Irwin 1981). The atlas data confirm a long summer breeding season and perhaps suggest two breeding peaks in Zone 5. There are two breed- ing seasons in Gujarat, India (Naik & Naik 1965), and in Kenya there is also some suggestion of two breeding peaks associated with the two rainy seasons (Brown & Britton 1980). Interspecific relationships: It freely joins mixed-species foraging flocks of swifts and, less often, of . A few nests are lost to usurp- ation by House Sparrows Passer domesticus. Substantial avoidance of high-altitude grasslands may be due to competition with the House Martin Delichon urbica of similar size, appearance and behaviour, which does frequent mountain tops. Complementarity with the Horus at higher elevation in the Drakensberg is also striking. Historical distribution and conservation: The only Little Swift 19th-century record from South Africa is of a cliff-breeding Kleinwindswael colony at Nelspoort (3223AA) on the border between the Great and Upper Karoos (Layard & Sharpe 1884; Stark & affinis Sclater 1903). The population explosion in southern Africa started early in the 20th century (Hare 1915; Gill 1928; This largely resident swift breeds from the Cape Province to Brooke 1965a) and by the 1930s it could be described as ‘now Morocco, Turkmenistan, India and Sri Lanka, and is replaced common in many parts, especially on the Karroo and High- to the east by a similar species, the A. nipalensis, veld’ (Gill 1936). The atlas data show that the Little Swift’s which is often considered conspecific. The Little Swift occurs range expansion and increase in numbers have continued. A throughout southern Africa and is expanding its local range species which has made such extensive use of man-made and populations within the region. Penry (1994) indicated that constructions for breeding, and which now occurs in greater its distribution in Botswana is restricted by the availability of numbers than ever before, does not give cause for conserva- surface water for drinking, and the map clearly shows its tion concern. absence from the drier parts with the deepest permeable sandy R.K. Brooke soils in the Namib and the Kalahari. It does not necessarily avoid arid conditions, as it is a common inhabitant of arid regions in some parts of its range, cf. the ranges of the races Recorded in 2220 grid cells, 48.9% A. a. galilejensis in the Middle East and of theresae in south- Total number of records: 30 730 western Africa (Brooke 1971d). Mean reporting rate for range: 23.4% It is probable that some atlas records are referable to the A. horus. This is not likely to have affected the mapping of this species, however. Reporting rates for vegetation types Habitat: It forages in the air over all vegetation types, but % 02550 prefers the more open grasslands and Karoo, except high- altitude alpine grasslands. It occurs regularly over water and Sweet Grasslands 40.1 drinks frequently (Penry 1994). It builds its nests, often in Grassy Karoo 30.7 large colonies, under dry overhangs, originally on cliff faces Nama Karoo 30.2 but nowadays much more frequently on human constructions Mixed Grasslands 28.5 such as bridges, water towers, grain silos and buildings. Central Kalahari 23.5 Where available, multi-storey buildings are preferred to Sour Grasslands 23.5 single-storey ones (Brooke 1963b, 1971g, 1974e). Moist Woodland 23.3 Movements: There is evidence from atlas data for partial Fynbos 22.6 migration of populations, but the habit of nonbreeding Little Succulent Karoo 19.8 Swifts foraging high in the winter skies, and only being visible Arid Woodland 18.7 while circussing near nest sites for a few minutes in the morn- East Coast Littoral 16.7 ing and the evening (e.g. Ferguson 1955), is possibly a con- Miombo 13.9 founding factor. Some of the seasonality in the models may, Mopane 13.7 therefore, be attributable to fluctuations in conspicuousness. E Zimbabwe Highlands 12.7 I believe that breeding forage only within c. 20 km of Valley Bushveld 12.6 a breeding site. It should be noted that the majority of records Afromontane Forest 8.9 from northwestern Namibia (including the Skeleton Coast Southern Kalahari 6.9 National Park), and from northcentral Botswana where the Alpine Grasslands 5.4 species does not breed (M. Herremans pers. comm.), are of Namibian Escarpment 4.1 nonbreeding birds from other parts of the range, presumably Okavango 2.7 in southern Africa. It is a winter visitor to the Zambezi Valley Namib 1.6 (e.g. Tree 1987i). Northern Kalahari 1.1 Apodidae: swifts 621

14û

LITTLE SWIFT 5 1 18û

22û 2 6

26û

3 7 30û Reporting rate (%) > 27.9 12.5 — 27.9 2.0 — 12.4

< 2.0 34û 4 8 18û 22û 26û 14û 30û 10û 34û

40 1 5 40 20 20

40 2 6 40 20 20

40 3 7 40 20 20

40 Occurrence reporting rate (%) 4 8 40 Breeding reporting rate (%) 20 20

J ASONDJ FMAMJ J ASONDJ FMAMJ Models of seasonality for Zones. Number of records (top to bottom, left to right): Occurrence: 123, 188, 1190, 1827, 1025, 2589, 5222, 514; Breeding: 4, 13, 119, 184, 64, 175, 477, 37. 622 Apodidae: swifts

LITTLE SWIFT

JAN — FEB JUL — AUG

MAR — APR SEP — OCT

MAY — JUN NOV — DEC

Reporting rate (%)

> 24.5 10.5 — 24.5 2.0 — 10.4 < 2.0

Seasonal distribution maps; one-degree grid.