[order] Passeriformes | [family] Sylviidae | [latin] Sylvia communis | [UK] Whitethroat | [FR] Fauvette grisette | [DE] Dorngrasmücke | [ES] Curruca Zarcera | [IT] Sterpazzola | [NL] Grasmus

Grasmus determination

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Medium-sized, quite slim but rather large-headed and long-tailed, perky warbler. Epitome of west Palearctic Sylvia, nearly all of which have distinctive males but rather similar female immature plumages. Crown and cheeks of male grey, of female and immatue brown. Sexes dissimilar, little seasonal variation.

Breeds over continental and oceanic W Palearctic in upper middle to lower middle latitudes, from boreal through temperate to steppe and Mediterranean zones. Mainly in lowlands, but in Switzerland and Caucasus between 1300 to 3200 m, or even higher. Avoids tall closed forest and densely vegetated wetland, requiring ample but discontinuous well-mixed and open cover of tall herbage, low bushes, and shrubs, usually on more or less dry, level or gently sloping, and fairly sunny terrain, sometimes by water or in marshy or fen areas, or in open woodland glades and edges, more often in woods of broad-leaved than of coniferous trees. Often occurs amid cultivation and sometimes in subalpine scrub or on moors or cliff slopes.

Sylvia communis is a widespread summer visitor to most of Europe, which constitutes >50% of its global breeding range. Its European breeding population is extremely large (>14,000,000 pairs), and was stable between 1970-1990. The species underwent a small increase overall during 1990-2000, with the majority of national trends increasing or, as in the case of the key population in Russia, stable.

During breeding season mainly insects, especially beetles, larvae, and bugs. In late summer, proportion of fruit taken increases, and on autumn migration and in winter quarters feeds predominantly on berries. Food obtained in bushes and herb layer by searching foliage and small branches.

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. [conservation status from birdlife.org]

Breeds May-June in North-West Europe, May-July in Finland, late April to mid May in West Germany, mid April to July in North Africa. Nest site built in bush or shrub or tall grass or herbs. Nest is a cup-shaped, usually quite deep, sometimes hemispherical, occasionally distorted probably by nestling to give elliptical rim, constructed of grass and herb stems and leaves with some roots, plant down, and cobwebs, lined with finer grasses and rootlets and long hair. 4-5 eggs are laid, incubation, 9-14 days, by both sexes, but only by female at night.

All populations migratory, wintering in sub-Saharan Africa, from Sénégal east to Ethiopia and south to South Africa. Initial autumn heading from continental Europe shows weakly expressed migratory divide: from west of 10°E, birds head west of south to Iberia; east of this, heading mainly south or east of south. Autumn migration begins late July, with main movement through central Europe August to mid-September, and stragglers to early October. Earliest records in Sénégal end of August, with main arrival a month later. Reaches Zimbabwe usually after mid-November, with main arrival December. Spring migration from Africa begins March. Reaches Gibraltar from mid-March, Camargue and Sicily from early April. Arrivals tend to be earlier in western than central Europe. Reaches Britain from early or mid-April, apparently on broad front, peaking early May in south-west, mid-May elsewhere; central Sweden from mid-May; Leningrad region from 2nd week of May, passage continuing to mid-June.