[order] Passeriformes | [family] Sylviidae | [latin] Sylvia sarda | [UK] Marmoras Warbler | [FR] Fauvette sarde | [DE] Sardengrasmücke | [ES] Curruca Sarda | [IT] Magnanina sarda | [NL] Sardijnse Grasmus

Sardijnse Grasmus determination

copyright: Eldert Groenewoud

12 cm; wing-span 13-17.5 cm; tail 4-5 cm. Close in size to Dartford Warbler but with 5-10% shorter tail (and thus less attenuated form). Small warbler, with spiky bill, high crown, short wings, and long tail; often has perky stance with weight forward. Plumage essentially dull blue-grey in (, browner below in ) and browner below and above in juvenile. Eye of adult ochre to red; eye-ring orange to red; bill base strikingly pink to orange. One call distinctive.

Breeds strictly within Mediterranean coastal and island areas, in warm situations with average July temperatures up to 24-26°C and relatively frost-free winters. Ascends to 400-500 m on Mallorca, on hillsides and mountains up to nearly 1000 m on Corsica. Prefers fairly uniform low cover, below height attractive to competitors, especially Dartford Warbler and Sardinian Warbler, as also Stonechat, all of which at times overlap with it. Mainly concentrated on parts of heathland (garigue) with much heath, palmetto or dwarf fan palm, and some grass (usually maintained as a result of poor soil, exposure, or fire) on islets and coastal slopes or hillsides, such areas occasionally being already invaded by scattered trees.

Sylvia sarda breeds only in Europe, where it is confined to the islands and islets of the western Mediterranean notably Corsica, Sardinia and the Balearic Islands. Its breeding population is relatively small (<75,000 pairs), but increased between 1970- 1990. Trends were not available for the Spanish and French populations during 1990- 2000, but the Italian population was stable, and the species is provisionally evaluated as Secure.

Chiefly small arthropods. Feeds mainly in low vegetation and on ground; also occasionally in trees and higher shrubs, not uncommonly sallying for insects like flycatcher.

This species has a large range, with an estimated global Extent of Occurrence of 50,000-100,000 km2. It has a large global population estimated to be 98,000-310,000 individuals (BirdLife International in prep.). 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]

On the Balearic Islands: eggs laid late March to early June. Corsica: eggs laid (mid-)late April to early July. 2 broods, perhaps occasionally 3. Nest is built in low scrub; 90-120 cm above ground, exceptionally to 190 cm. Nest: well-constructed and substantial cup, often with thickened rim, of dry grasses, stems, and leaves, often with vegetable down and sometimes wool, bits of bark, and spiders‘ webs and cocoons; lined with finer material including grass, roots, hair, plant down, and occasionally a few feathers. Eggs are sub-elliptical to short subelliptical, smooth and slightly glossy; white or grey-white, with buff to red-brown and grey spots often concentrated at broad end, or sometimes with heavy red-brown blotching and lighter grey and brown speckles. Clutch: 3-4 eggs incubated 12-15 days. Young flegde after about 12 days.

Corsican and Sardinian populations partially migratory, many birds remaining within breeding range all year; populations of Balearic Islands mostly sedentary. Passage to and wintering in north-west Africa reported mostly November-March. Occasional reports north of breeding areas are presumably vagrants or overshooting spring migrants.