Isabelline Shrike Lanius isabellinus Scientific name definitions

16·5–18 cm; 26–33·5 g (see also L. phoenicuroides). Rather small, compact but long-tailed shrike, with calls and behaviour as L. collurio. Male nominate race has pale greyish crown, tinged isabelline on forehead, complete black mask with narrow whitish border above, rather warm sandy grey on upperparts to upper rump, rufous lower rump and reddish-brown tail; upperwing contrastingly blackish, feathers edged pale sandy buff, white patch at base of primaries; throat whitish, underparts sandy cream to isabelline; iris brown; bill dark brown to dull blackish; legs grey-black. Female resembles male but slightly duller, with browner and less extensive mask, smaller patch at base of primaries (sometimes absent), slightly scaled underparts, and pink bill base, legs browner or greyer. Juvenile is greyish brown with narrow blackish vermiculations above, tail rufous-brown, creamy buff with brownish vermiculations below, throat and narrow band down to undertail-coverts generally plainer; first-winter has remnants of juvenile barring above and below, whitish-buff supercilium, brown ear patch, subterminal dark bars on tertials, lower rump, uppertail-coverts and tail, white patch on base of primaries little developed. Races differ mainly in coloration and size: <em>arenarius</em> has relatively shorter and less pointed wing than nominate, is also pale, male uniform greyish or sandy grey above, less well-defined facial pattern, pale lores, pale primary patch small and less white, tail dull cinnamon (less rufous), underparts sandy pinkish to pale buff, whiter on centre of belly; tsaidamensis is very like last but longer-winged (up to 102 mm, vs. 88–94 mm in nominate) and slightly paler.

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Breeds in tamarisk (Tamarix) thickets in river valleys, patches of scrub in dry steppe, in mountains extending up to perhaps c. 2000 m. In non-breeding quarters, found in India and Pakistan on edges of cultivation in semi-desert and among sparse acacia (Acacia) and tamarisk trees, often in open grassland near water; in E Africa occurs in relatively open country up to c. 2400 m with scattered bushes, and in dry lowlands, generally preferring drier and more thorny vegetation than that used by L. collurio, but in Chad observed in marshy areas. As with other shrikes, from several of which it seems not to be segregated in winter quarters, foraging requirements include much exposed soil.

Migratory. Precise range in non-breeding season, especially in Africa clouded by previous lumping of this species with L. phoenicuroides, with many older records outside main range unascribed to taxon. Non-breeding grounds from sub-Saharan Africa (mostly E from Nigeria, S to NE Tanzania) and Arabia E to Pakistan and NW India ; present in winter quarters Nov–Mar, in extreme cases from Oct and up to May, but reaches C Sudan and Horn of Africa mainly from Nov and N Nigeria from early Dec; and has been observed in Kazakhstan as late as end of Oct. Heading in autumn varies between SW (some nominate) to Arabia and Africa, and S to SE to Iraq, S Iran, Pakistan and India (most <em>arenarius</em> and tsaidamensis); regular autumn passage migrant through Iraq in Sept. Can be faithful to same wintering site in consecutive seasons. Those wintering in Nigeria must head almost due W within Africa. Return migration in spring apparently along same routes as used in autumn; peak spring movement in NE Africa mid Apr, in NW India in Mar; occasional in Israel and NE Egypt (Sinai) in spring. Breeding population of nominate race reaches S Mongolia at end May; males arrive on breeding grounds earlier than females. Vagrants recorded increasingly in Europe , even in NW (Britain), mainly in autumn, as well as S to Morocco.

Most data pertain to either this species or L. phoenicuroides. Almost exclusively insectivorous. Prefers mostly beetles (of families Elateridae, Tenebrionidae, Scarabaeidae) and crickets and grasshoppers (Orthoptera), with other invertebrates taken less often; also some small vertebrates taken, including voles (Microtini), small lizards, and small birds such as leaf-warblers (Phylloscopus) and pipits (Anthus) and wagtails (Motacilla). Uses sit-and-wait foraging technique, utilizing a variety of lookouts, including wires, fence lines and tree branches ; mean height of perch 2·1 m on non-breeding grounds in Kenya (almost certainly refers mostly to L. phoenicuroides. Most insects taken on ground (73% of 175 prey items in Kenya, but again data almost certainly mostly pertain to L. phoenicuroides). Impaling of prey not rare.

Considered a much better singer than L. cristatus, and calls somewhat reminiscent of those of L. collurio, but courtship calls more nasal “tschre…tschre…” (race arenarius), while contact call of nominate “kscha-kscha”. Male territorial calls described as “zea-zea”, but in presence of mate change to “ko-ick”, and “zautzat…zautzat” and “tzautzat… tzautzat”, respectively. When disturbed, “zeee” or sometimes “dzhikh-dzhikh-dzhikh”; wide variety of alarm calls reported, from typical “ktschaaä” and chattered “chak-chak-chak” to rattling “krkrkrkr…”; “tschek-tschek” can be given as alarm, as well as during courtship. Intraspecific begging calls of mates are series of “kikikiki…” or “keee-keee-keee” (nearly identical to begging calls of juveniles). Song said to be a relatively quiet warble, often replaced by harsher and squeakier melodies; mimics other birds.

Season Apr–Aug in W China; usually single-brooded, but double-brooding reported in China. Mating normally begins with loud calls by male, which often followed by gliding display-flights of competing males; male has aerial display, flying to and fro in front of female while calling loudly, also bowing perched display with fanned tail raised, this often followed by fluttering flight by both partners. Nest-site chosen by male; nest  a deep open cup made from twigs, bark, rootlets, leaves and grass, lined with grass stems, moss and similar soft material (resembles nest of L. collurio), built c. 0·3–3 m but generally low (mean 1–2·5 m in various studies) above ground in bush, often thorny one, e.g. Tamarix ramosissima, Elaeagnus angustifolia and Populus euphratica in Gansu, China. Clutch 4–6 eggs (mean 4·6), pale bluish green, with pale brown spots concentrated toward broad end, mean size 22–22·8 mm × 16·7–18·5 mm (from two different Chinese studies), mean mass c. 3·4 g; replacement clutches frequent if earlier ones lost; incubation by female, fed on nest by male, period 15–16 days, starting with first egg; nestling period c. 12–15 days; young fed by parents for c. 1 month after leaving nest. Parasitized by Common Cuckoo (Cuculus canorus) in China and probably elsewhere (see L. phoenicuroides). In Gansu, overall breeding success was estimated at > 68%, with most failures apparently due to intraspecific competition with neighbouring pairs destroying nest-sites, but hatching success was 82·5% and 58·6% of nestlings fledged. First breeding at one year of age.

Not globally threatened (Least Concern). Not well known; probably not uncommon in much of range, but locally uncommon. Global population size not quantified, but believed not to be close to the thresholds that would indicate that this species is at risk. Protected in most countries; in some listed as “endangered”. A decrease in the use of agricultural pesticides, combined with conservation of semi-open habitats (pastures, meadows) with scattered bushes, would probably be the most effective measure to ensure its future. Present in several national parks and other protected areas in its non-breeding range.