European Roller Dreds of Square Kilometres (Pers

sometimes in concentrations over hun- European Roller dreds of square kilometres (pers. obs in Europese Troupant northern Botswana). Numbers can fluc- tuate widely between summers and re- Coracias garrulus gions, with an apparent tendency for more individuals to move further south The European Roller is a Palearctic mi- in wetter years (Tree 1987a; pers. obs). grant which breeds in southern Europe, Interspecific relationships: During North Africa (Algeria and Tunisia) and summer there are three Coracias rollers western Asia; in the nonbreeding season in southern Africa with somewhat simi- it is widely, but exclusively, distributed lar feeding ecology and a broad overlap throughout sub-Saharan Africa (Fry et al. in habitat: European, Lilacbreasted C. 1988). It is relatively common in coastal caudata and Purple C. naevia Rollers. northern KwaZulu-Natal, eastern Swazi- The European has the widest distri- land and the eastern Transvaal lowveld to bution and the greatest habitat tolerance, the upper–middle Limpopo drainage, but is the least common in any biome, northcentral Namibia, the northern Kala- except in miombo, where it outnumbers hari in Botswana and the central plateau the Purple Roller. Contrary to parts of of Zimbabwe. eastern Africa where it outnumbers all Almost throughout its southern Afri- Afrotropical rollers (Brown & Brown can range, observations are scattered, 1973), Lilacbreasted Rollers are 5–10 indicating erratic occurrence. Although times more common and Purple Rollers widespread, it is not abundant in south- 2–3 times more common than European ern Africa: average densities in roadside Rollers in southern Africa (Herremans et counts were 1 bird/55 km in central and al. 1993b; Herremans & Herremans- northern Namibia and 1 bird/114 km in Tonnoeyr 1994g). northern and eastern Botswana (Herremans et al. 1993b), Historical distribution and conservation: It has de- which is 50–100 times less than on the principal wintering clined dramatically over most of Europe (Cramp et al. 1985). grounds in eastern Africa (Fry et al. 1988). Its status in southern Africa has previously been given as C. g. garrulus breeds in the western Palearctic and consti- abundant, with the northern parts of Botswana, Namibia and tutes 60% of the southern Africa population, while semenowi Zimbabwe indicated as principal nonbreeding grounds (Fry (40%) breeds in the eastern part of the range and appears to et al. 1988). The much lower abundance presented here does migrate mainly to southern Africa (Clancey 1974; Fry et al. not reflect any documented recent decrease in abundance in 1988). The world population has been estimated to be four the region (Herremans et al. 1993b). The European Roller is million birds, just prior to breeding (Fry et al. 1992). not known to be threatened in southern Africa, and factors in It is the most gregarious of the Coracias rollers in south- this region (except perhaps for drought) are unlikely to be im- ern Africa: although apparently mostly solitary in mid- plicated in the decreases in Europe, also because most birds summer, birds are in fact usually in loose nomadic associa- from the western parts of the range are not expected to migrate tions. It is conspicuous and easy to identify, resulting in reli- to southern Africa. able atlas data. M. Herremans Habitat: It is a summer visitor to a variety of woodlands, bushveld and grassland vegetations. It avoids the open arid areas in the west. It is recorded over a wide range of altitudes Recorded in 1199 grid cells, 26.4% and habitats, ranging from edges of evergreen forest to open Total number of records: 5058 grassland and Karoo. It is most common in open woodland; Mean reporting rate for range: 6.3% it is marginal in more open vegetation types with less- developed woody cover, such as the central Kalahari, Karoo and grassland biomes. Movements: Southward migration is concentrated along Reporting rates for vegetation types the Nile and Great Rift valleys (Fry et al. 1988). It reaches the % 0816 far north of southern Africa by October, but the majority only arrive December–January. Peak numbers are present in south- Arid Woodland 11.5 ern Africa in February, but movements of flocks may occur Mopane 10.7 throughout the summer (Penry 1990b; Herremans et al. Miombo 7.6 1993b). In the southern half of the region, fewer birds are Northern Kalahari 7.5 present, and they begin to arrive only in December. Depar- E Zimbabwe Highlands 5.7 ture is mainly in March; there is spectacular migration along Moist Woodland 5.6 the coast of northeastern Africa in April (Fry et al. 1988, Okavango 4.2 1992). Occasional birds remain into May and exceptionally East Coast Littoral 3.0 stay throughout the austral winter (Irwin 1981; Tarboton et al. Central Kalahari 1.6 1987b). It is one of the latest Palearctic migrants to reach peak Grassy Karoo 1.3 numbers in the region, and clearly shows the ‘classic’ pattern Valley Bushveld 1.0 of slow arrival and rapid departure (Underhill et al. 1992b). Sweet Grasslands 1.0 Upon arrival, just before departure and during migration, Sour Grasslands 0.8 it forms larger flocks, sometimes of many hundreds (Hoesch Mixed Grasslands 0.8 & Niethammer 1940; Penry 1990b; Herremans et al. 1993b). Also marginallyNama in Nama Karoo Karoo, Southern 0.5 Kalahari, Namibian Escarpment, During adverse weather, migratory flocks are grounded, Fynbos,Southern Alpine Grasslands, Kalahari Namib 0.3 and Succulent Karoo. Namibian Escarpment 0.3 Fynbos 0.2 Alpine Grasslands 0.2 Namib 0.1 Succulent Karoo 0.0 Coraciidae: rollers 677

14û

EUROPEAN ROLLER 5 1 18û

22û 2 6

26û

3 7 30û Reporting rate (%) > 14.2 7.1 — 14.2 2.0 — 7.0

< 2.0 34û 4 8 18û 22û 26û 14û 30û 10û 34û 40 1 5 20

40 2 6 20

40 3 7 20

40 Occurrence reporting rate (%) 4 8 20

J ASONDJ FMAMJ J ASONDJ FMAMJ Models of seasonality for Zones. Number of records (top to bottom, left to right): Occurrence: 142, 37, 18, 18, 552, 1296, 392, 39.