Lesser Striped Swallow October for Ampliformis

66 Hirundinidae: swallows and martins

ing latitude for unitatis. The departure of birds from their breeding grounds is spread over several weeks and is probably influenced by the stage of breeding of individuals. Populations start to decline as early as February–March in most regions. Some nests in the northern Kruger National Park were occupied throughout the year but different individuals used the nests during the summer and winter months, indicating that ‘residency’ does not necessarily involve the same individuals (R.A.E. pers. obs.). Breeding: A summer-breeding pattern is shown by the race unitatis in the eastern Cape Province (Zone 8), KwaZulu-Natal (Zone 7) and Transvaal (Zone 6), with most breeding recorded August–May and peaking Novem- ber–December. Breeding starts earlier in the Transvaal than in the eastern Cape Province. In Zimbabwe breeding occurs throughout the year (Irwin 1981), but this contains records of unitatis on the plateau and ampliformis in the west, and the majority of records refers to unitatis whose breeding peaks August–December. In Namibia and northern Botswana (Zone 1), breeding was recorded March– Lesser Striped Swallow October for ampliformis. Skinner (1995a) indicated peak Kleinstreepswael egglaying for this race in May. Interspecific relationships: It often occurs alongside Hirundo abyssinica the Greater Striped Swallow but usually one species tends to be much more common than the other in areas of over- This common species is distributed along the coast and lap. Because both of these species use man-made structures adjacent interior of the eastern Cape Province and Trans- for breeding, they may compete for nest sites and the kei, throughout much of KwaZulu-Natal, the Transvaal smaller Lesser Striped Swallow may be at a disadvantage woodland areas, and most of Swaziland and Zimbabwe. In in such situations. There could also be competition with Botswana, it occurs in the east and commonly in the the much larger Redbreasted Swallow H. semirufa for nest Okavango, and in Namibia is found along the Kunene and sites, but that species usually nests in more constricted sites Kavango rivers, the Caprivi Strip, and scattered records than the two striped swallows. Lesser Striped Swallow further south. This is one of the most abundant African nests are regularly usurped by Whiterumped Swifts Apus swallows; it ranges over the greater part of Africa south of caffer (Fry et al. 1988). the Sahara, with the exception of the open regions in the Historical distribution and conservation: Like many south and southwest. It is frequently confused with the Hirundinidae, this species has benefited from nesting in similar Greater Striped Swallow H. cucullata in southern man-made structures and has probably increased, at least Africa. in density, in many areas owing to this habit. Habitat: It occurs in a variety of woodland and savanna habitats, except for semi-arid Kalahari savannas. Within R.A. Earlé and M. Herremans these regions it can also be found in cultivated and sub- urban areas. It is more common in lower-lying than higher- lying areas within its range. It is known to nest frequently Recorded in 1243 grid cells, 27.4% on riverbanks and trees (Aspinwall 1980; Skinner 1995a). Total number of records: 23 708 Movements: This species shows complex patterns of Mean reporting rate for range: 30.0% movement in the region. It is largely a summer-breeding migrant in South Africa, but some birds are present throughout the year, especially in the lower-lying eastern areas along the KwaZulu-Natal coast and in the lowveld of the Transvaal and Swaziland (e.g. Tarboton et al. 1987b). A winter exodus is also apparent in Zimbabwe but Reporting rates for vegetation types the presence of birds in this country during the winter is % 02550 more frequent than in most of South Africa, and birds from the south may pass through or winter in Zimbabwe. It has East Coast Littoral 46.3 been suggested that the Zimbabwean breeding population Moist Woodland 36.6 leaves that country and is replaced by South African Okavango 34.2 migrants during the winter (Irwin 1981). In the Caprivi Miombo 32.6 Strip, the Okavango region, Chobe and Linyanti rivers, and Valley Bushveld 30.7 the Zambezi upstream from Victoria Falls, the distinct race Arid Woodland 28.7 H. a. ampliformis is primarily a winter-breeding visitor, E Zimbabwe Highlands 25.3 mainly from March–October (Brewster 1991; Herremans Mopane 21.4 et al. 1994b; Herremans 1994d; Skinner 1995a), but pas- Sour Grasslands 14.9 sage of the southern race unitatis through this area is likely Afromontane Forest 14.0 in August–September and March–April (Herremans Northern Kalahari 7.1 1994d). Mixed Grasslands 5.8 The models for Zones 5–8 suggest reduced overwin- Nama Karoo 4.3 tering, and later arrival and departure times with increas- Fynbos 2.1 Hirundinidae: swallows and martins 67

14û

LESSER STRIPED SWALLOW 5 1 18û

22û 2 6

26û

3 7 30û Reporting rate (%) > 35.6 18.5 — 35.6 2.0 — 18.4

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

30 40 1 5 20 20 10

30 40 2 6 20 20 10

30 40 3 7 20 20 10

30 Occurrence reporting rate (%) 40 4 8 Breeding reporting rate (%) 20 20 10

J ASONDJ FMAMJ J ASONDJ FMAMJ Models of seasonality for Zones. Number of records (top to bottom, left to right): Occurrence: 262, 3, 0, 151, 2453, 3334, 2553, 988; Breeding: 17, 0, 0, 52, 115, 475, 418, 225. 68 Hirundinidae: swallows and martins

LESSER STRIPED SWALLOW

JAN — FEB JUL — AUG

MAR — APR SEP — OCT

MAY — JUN NOV — DEC

Reporting rate (%)

> 38.6 18.4 — 38.6 2.0 — 18.3 < 2.0

Seasonal distribution maps; one-degree grid.