Sylvia borin is a widespread summer visitor to much of Europe, which constitutes >75% of its global breeding range. Its European breeding population is extremely large (>17,000,000 pairs), and was stable between 1970-1990. Although there were declines in France during 1990-2000, other key populations in Sweden, Finland, Germany, Romania and Russia were stable, and the species probably remained stable overall.

Breeds in middle and upper middle latitudes of west Palearctic in continental and marginally oceanic, mainly temperate climate. Preference for shrubby clusters of green alder, lower levels in shady broad-leaved scrub often moist and by water, although sometimes in copses of warm dry soils. Avoids pure coniferous stands, dense plantations, and towns, and occurs only occasionally in gardens and parks.

Breeds March-July in North-West Europe, April to mid July in West Germany, end May to second half of July in Finland. Nest site is built in low tree or bush or tall herbs. Nest, substantial cup, loosely constructed on outside and underneath, of grass and herb stems and leaves, with some twigs and roots, up to 30 cm long, plus a little plant down and cobwebs, lined with finer grasses and rootlets and long hair. 4-5 eggs are laid, incubation, 11-12 dayas, by both sexes, but male only during daylight hours and then less than female.

Chiefly insects in breeding season, mainly plant material at other times. Searches vegetation to pick insects from foliage and twigs, sometimes hovering or sallying out to catch flying insects.

This species has a large range, with an estimated global Extent of Occurrence of 10,000,000 km². It has a large global population estimated to be 10,000,000 individuals (Shirihai et al. 2001). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

All populations migratory, wintering extensively in Africa south of c. 10°N in west and 3°N in east, south to South Africa. Within Europe, autumn heading chiefly south to south-west (and reverse in spring): to Iberia from western and central Europe (including Britain and western Scandinavia), to Italy from Finland and north-east Europe. Prolonged migration at both seasons. In Britain, movement south begins mid-July, larger number leaving from mid-August, with peak (including drifted continental birds) early September at eastern observatories, but later in west. Passage through Switzerland chiefly August, adults continuing to mid-September, juveniles markedly later, to mid-October. Prolonged passage early August to early November (mostly late August to early October) on Malta. Arrives in northern parts of winter quarters from mid-September, in southern Africa not until December. Leaves winter quarters from February. Passage through Mediterranean area mainly in early May; arrival at breeding grounds also mainly early May in south and central Europe, late May or early June in north.

article number 1 Title
Changes in body condition from spring migration to reproduction in the Garden Warbler Sylvia borin : a comparison of a lowland and a mountain population
Author(s): Widmer M. & H. Biebach 2001
Abstract: Long-distance migrants often arrive on their breeding grounds with large fat stores . Two expl anations for this phenomenon are (1) that large fat stores at arrival are needed to speed up the breeding..[more]..
Source: Ardea 89(special issue) : 57-68
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article number 2 Title
The study of bird migration across the Western Sahara; a contribution with sound luring
Author(s): Marc Herremans
Abstract: During spring and autumn migration 2003, the Swiss Ornithological Institute set up a concerted project in Mauritania to study bird migration across the Sahara. I participated with a side project using..[more]..
Source: Report of field research in Mauritania
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article number 3 Title
Garden Warbler Sylvia borin migration in sub-Saharan West Africa: phenology and body mass changes
Author(s): ULF OTTOSSON et al
Abstract: The Garden Warbler is a classic subject for the study of Palaearctic-African bird migration strategies. Most studies have considered the situation close to the breeding areas, while the African and ..[more]..
Source: Ibis (2005), 147, 750-757
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