Rock Thrush – Monticola saxalitis

Field characters: 18.5 cm; wing-span 33–37 cm. 10% smaller than Redwing and Blue Rock Thrush.

Strong-billed, rather long-bodied, rock-haunting bird, with shape suggesting large short-tailed chat rather than thrush. ? essentially blue, black, and white above, with rufous body and tail; ? basically buff, pale-spotted above and barred below except on rufous tail. In winter and 1st autumn, plumage copiously scaled with pale tips which obscure above patterns. Juvenile like ? but paler due to even more copious mottling. Almost unmistakable among wild birds of west Palearctic (? and immature always pale-throated, unlike Blue Rock Thrush).
Flight usually low and floating, with full beats of wings as slow as Turdus thrushes but with short tail giving appearance of large chat; capable of considerable acceleration when escaping.
Stance strongly recalls large wheatear, with usually upright attitude; characteristically wags tail, with obvious upward jerk and loose flirt. Gait essentially hopping but long-paced, allowing even progress on flat ground and nimbleness over rocks.

rockthrush1Habitat
Breeds in west Palearctic in lower middle latitudes in continental warm temperate, steppe and Mediterranean montane zones, on sunny, dry often stony hollows or terraces, preferably dotted with stunted trees or shrubs serving as perches. In southern Switzerland, also on rocky heaths and in vineyards from 500 m, but mainly at 1500–2700 m. Forages over some distance from nest, down to hayfields and farmland, using rocks, walls, roofs of buildings, and bare branches or treetops as hunting look-outs. In Spain, nests on barren hillsides with boulders and crags, chiefly at c. 1250–2300 m. In Germany, as elsewhere towards north of European range, many sites occupied last century (e.g. ruined castles on the Rhine, heaps of debris) were deserted before or soon after its end. In winter in tropical west Africa, lives in savanna and in erosion areas with scattered low bushes and stony gullies, or better-wooded land, even gardens.

rock-thrush3Distribution
Long-term decline in range (especially southward contraction) and numbers; causes unclear, but probably include loss of habitat (breeding and perhaps winter) and possibly climatic change. Recent range decrease reported from Slovakia, Hungary, Iberia, Ukraine, and Moldova.

Population
Most countries report decreases, marked in Slovakia, Hungary, and Ukraine. Stable Switzerland, Greece, Rumania, and perhaps Slovenia and Bulgaria, with apparent increase Croatia; trend uncertain Albania and Turkey. We include the latest population details here for not only Spain, but also surrounding countries (plus Morocco).
France
Probably over 1000 pairs.
[Update: 10 000–20 000 pairs (2000), trend unknown (BirdLife International 2004).]
Spain
 3500–4800 pairs.
 [Update: 2500–10 000 pairs (1998–2002), trend unknown (BirdLife International 2004).]
Portugal
100–1000 pairs 1978–84.
 [Update: 50–500 pairs (2002), stable (BirdLife International 2004).]
Morocco
Scarce; probably some decline.
Movements
Migratory. Most winter in Afrotropics, birds from eastern China travelling at least 7500 km from breeding to wintering grounds. A few birds appear to winter in Africa north of Sahara and in Arabian peninsula. Nocturnal migrant, usually travelling singly or in loose aggregations, often with Blue Rock Thrush. Main wintering area lies north and east of central African rain forests: from northern Nigeria and Cameroon (south to c. 8°30?N) east to Eritrea and from there south to at least 9°S in Tanzania.
 Mediterranean populations of southern Europe and north-west Africa begin to disperse from breeding sites in August, most having left by late September. Appears to cross Sahara on broad front from Morocco to Sinai, but especially common in central section. Reaches Chad mid-October, Nigeria late November. Occasional November–January records in Morocco, Ahaggar massif, Libya, and Egypt may indicate wintering north of Sahel zone by very small number. Most sites south of Sahara vacated by mid-March with stragglers remaining until at least mid-April. Passage noted in Sahara and on North African coast March–May with peak in late March and early April. However, first arrivals at southern breeding sites are usually in February, demonstrating that early passage in Africa overlooked. Northernmost European breeding sites usually reached April

rock-thrush2Food
Mostly large insects (especially beetles, Lepidoptera larvae, and Orthoptera); also a variety of berries. Feeds mainly by flying from perch (rock, tree, etc.) on to prey on ground; may eat several items while on ground, sometimes running or hopping a few metres between each before returning to perch.

Social pattern and behaviour
Usually solitary. Small loose-knit flocks, notably of young birds, occur on spring migration. In winter, Tanzania, ? and ? probably defend separate territories. No evidence for other than monogamous mating system. Pair-bond presumably breaks down outside breeding season, but may be renewed for several years on breeding grounds. Song-display mainly by ?, much less often ?, given perched, in song-flight, or normal flight. Song from perch often a response to intrusion by nearby ?, leading to song-duel. Song-flight begins from perch. ? takes off suddenly, initially staying low, then ascends steeply with slow powerful wing-beats. Bird begins singing during ascent, reaching maximum output at top of ascent where bird soars, flutters rapidly, and typically introduces mimicry into song; then suddenly plummets, not singing, for 15–20 m with wings and tail outspread. Usually, bird does not land after descent but, apparently using momentum of plummet, ascends for a 2nd song-flight, less high, however, than 1st. Depending on intensity, bird repeats song-flight 2–3 times or more. Song-flight always ends on perch, with low variant of song.

Voice
Song, given by both sexes but mainly by ?, similar to Blue Rock Thrush, but softer and more flowing. Comprises melodious fluting phrases, often with obvious mimicry. Many species mimicked, Chaffinch song most regularly. Contact-alarm call single or short series of ‘tak’ sounds, often accompanied by tail-flicking. Warning- and alarm-calls include a plaintive mournful pipe, not unlike Bullfinch, and in greater alarm, an emphatic rapidly repeated ‘schack-schack’.

Breeding season
Earliest eggs late April, main season May–June, apparently throughout range. 1–2 broods.

Site
Horizontal crevice in rock-face, wall, ruin, or crag, under boulder on steeply sloping ground, or occasionally in tree-hole. Nest: neat cup of grass, rootlets, and moss, lined with finer rootlets and moss.

Eggs
Sub-elliptical, smooth and glossy; pale blue, often unmarked, or with some faint speckles of red-brown at broad end. Clutch: 4–5(–6).
Incubation…14–15 days.

Fledging Period
14–16 days.

References
BirdLife International/European Bird Census Council (2000) European Bird Populations: Estimates and Trends. BirdLife Conservation Series No. 10. BirdLife International, Cambridge.

Shirahai (1996) The birds of Israel. Academic Press, London.

Birds of the Western Paleartic. Oxford University Press

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