Isabelline Wheatear Oenanthe isabellina Scientific name definitions

16–17 cm; 21–39 g. Resembles non-breeding O. oenanthe, but slightly larger and paler , larger bill , longer legs (giving more upright stance), comparatively long and pointed wings (looking broader in flight), and relatively short tail. Male is yellowish-grey (isabelline) from crown to back  and wings (black alula), with strong preocular white supercilium becoming weak and whitish-buff behind eye, blackish loral line , white face and throat with buff-tinged ear-coverts, neck side and breast, white underparts ; white rump and tail, latter with black central feathers and broad black terminal band  ; bill and legs black. Female  and first-winter very like male, but loral line paler  , upperparts paler, buff and whitish edgings of wing feathers broader. Juvenile is like dull female, with buffier supercilium, faint spotting above and freckling below .

NE Greece, S Bulgaria, Middle East and S & E Ukraine E to Transbaikalia, Mongolia, Inner Mongolia, NC China and W Pakistan; winters in W Africa E across Sahel to Arabian Peninsula and S Asia (Pakistan and NW India), locally in Middle East.

Migratory; winters in Africa (mainly Sahel zone and NE & E Africa), Arabian Peninsula and SW Asia. Autumn migration at night on broad front, W populations heading SW over E Mediterranean, passage through Tunisia late Aug to late Nov, Egypt mid-Aug to mid-Oct, Israel mainly mid-Aug to mid-Oct (some overwintering), Jordan Aug to early Oct, E Arabia Aug–Nov (mainly Sept), arriving in W Africa mainly in Oct, in Sudan, Eritrea and Somalia Sept, inland Ethiopia and Kenya Oct, Tanzania Dec; vagrant in Seychelles recorded Nov. Most of Ukrainian population considered probably to migrate down E side of Black Sea; E parts of range vacated from late Jul (some remaining in Gobi into Oct), suggesting that populations may undertake strong W movement before crossing W Himalayas to reach SW Asian wintering grounds (passage Ladakh and Kashmir Aug–Oct and Mar–Apr). Some local movements noted in winter quarters, with birds in Kenya disappearing after Oct–Nov rains but reappearing when drier; also moves in response to grass fires. Spring departure in W mainly Feb–Mar, with passage Algeria to Libya Feb–May (peak Mar), Egypt mid-Mar to mid-Apr (now rare but regular spring visitor, Morocco), mainly end Feb to early Apr in Israel and Mar to mid-Apr in Jordan; mainly late Feb through Mar in E Arabia; arrival back in SW Iran from early Feb and in Turkmenistan late Feb, S Kazakhstan mid-Mar, Mongolia end Mar to mid-Apr. Vagrants recorded in NW Europe and elsewhere.

Invertebrates and vegetable matter; mainly insects 2–40 mm in length, and in particular beetles and ants. Animal prey recorded includes adult and larval beetles of at least 13 families, hymenopterans (ichneumons, ants, bees and wasps), adult and larval flies of at least four families, adult and larval moths of at least three families, caddis flies, lacewings, ant-lions, bugs, termites, grasshoppers, mole-crickets, cockroaches, mantis pupae, dragonflies, mites, spiders, harvestmen, solifugids, scorpions, millipedes, woodlice and molluscs; occasionally also small vertebrates. Small seeds (e.g. of legumes and Ceratocarpus turkestanicus) also occasionally taken. Two major studies of diet in Palearctic yielded broadly similar results: in Turkmenistan, stomachs of 218 birds from throughout year held, by number, 38% ants and 36% termites, and 56% of stomachs held ants, 52% beetles, 28% termites, 24% caterpillars, 16% grasshoppers and 14% bugs; in SW Iran, stomachs of 37 birds from throughout year held 61% ants, and 84% of stomachs held ants, 78% beetles, 30% bugs, 30% spiders, 22% termites, 22% other hymenopterans, 11% grasshoppers and 11% woodlice (96% of items less than 10 mm). Other studies reveal same general choices and proportions, although beetles sometimes predominate in smaller samples. Nestlings provisioned with softer-bodied prey than that eaten by adults: of 404 items brought to week-old nestlings in Turkmenistan, 61% were caterpillars, 25% myriapods, 5% beetles, 5% spiders, 3% adult lepidopterans, 1% grasshoppers and a few ants; elsewhere young seen to be fed with lizard 5 cm long, also an earthworm. In winter quarters, beetles, grasshoppers and ants (including Messor barbarus) targeted. Forages mostly in cooler parts of day, using bound-and-grab manoeuvres, perch-and-pounce sallying, sallying after flying insects and sally-gleaning; these four techniques used in, respectively, 86%, 8%, 4% and 1% of foraging attempts in one study in Kenya, but in Senegal perch-and-pounce and aerial sallying were more important than bound-and-grab, the difference being caused by habitat structure. Also digs in ground in early spring, when few invertebrates on surface, and will then also seek food down rodent burrows.

Song  very distinctive, mainly by male (occasionally by female), in flight and on ground in both breeding and winter quarters (often softer in winter), a loud rich melodious rambling series of variable phrases 3–7 seconds long, with pauses of 2–6 seconds, each phrase consisting of remarkable jumble of whistles, grating, twanging and “chack” notes, sometimes with excellent mimicry (of many other birds, also reputedly of e.g. shepherd’s whistle, squealing puppy, donkey bray); in flight, song begins (in ascent phase) with accelerating series of downslurred “chyup” notes, and shifts (in descent phase) into rapid jumble of metallic, crackling, buzzy, twangy notes. Subdued song or subsong in winter quarters, for territorial defence, often in hottest part of day, a random sequence of very high and fairly low whistles, clucks, bleats and wails. Calls  include whistled “wiiu” and harsh “chack”, often in combination; disjointed whistles and “kwot-kwot” sounds in courtship display.

Mid-Apr to mid-Jul in Israel and Apr–May in Jordan; Mar–Jun in Armenia and Baluchistan; sometimes as early as mid-Feb in Turkmenistan, but normally late Mar to Jul in S Russia; late Apr to mid-Jul in Mongolia. Sometimes bigamous. Average territory size in SW Iran 2·2 ha (range 0·52–6·9 ha), in Russia 2·7 ha (1·1–6·4 ha), size increasing with age and number of mates (average for older bigamous males 3·2 ha); in Turkmenistan 0·7–4·2 ha (although figures only approximate, as many territories overlap by up to 20–50 m); in Transbaikalia all territories smaller, 1·2–2 ha. Nest a shallow, bulky cup of dried grass, roots and hair, lined with hair, wool and feathers, placed deep (0·9–3·1 m, mean c. 2 m) in rodent burrow or burrow of similar mammal, less often in old bee-eater (Meropidae) hole or occasionally natural hole or crevice; in Azerbaijan, fluctuations in a local nesting population could have been related to the variable abundance of a burrowing rodent, Meriones sp. (1 Aspinall, S. (2009). Relationship between nesting Isabelline Wheatears Oenanthe isabellina and a burrowing rodent (a jird Meriones sp). Sandgrouse. 31(2): 179–181. Close ); in the Tibetan plateau most nests are in pika (Ochotona cruzionae) burrows, at 1·25 m deep on average (2 Li, S. and Peng, W. (2014). Nest-site selection by lsabelline Wheatears Oenanthe isabellina on the Tibet plateau. Forktail. 30: 132–133. Close ). Eggs 4–7, pale blue to almost white, sometimes with reddish spots; incubation period 12 days in one account, 14–15 in another; nestling period 13–15 or 15–17 days; post-fledging dependence c. 14 days. In Turkmenistan, 82% of 29 eggs hatched, 62% of eggs laid produced fledged young ; in Transbaikalia, hatching success 84·8%, with 4·4 fledglings per pair; in Volga-Ural region 43% of total eggs laid produced fledglings; in Ukraine, steppe stoat (Mustela eversmanni) a significant predator, and nests also lost to flooding and ant invasions; loss of nests higher if burrow occupied by rodent.

Not globally threatened (Least Concern). Generally common to very common. European population in mid-1990s estimated at 423–1378 pairs, with additional 100,000–1,000,000 pairs in Russia and same in Turkey; by 2000 total European population (including European Russia and Turkey) revised to 2,100,000–6,300,000 pairs and considered generally stable. In optimal habitat (with many rodent holes) around Caspian Sea densities can reach 3–4 pairs/ha (300–400 pairs/km²), but this exceptional; in good habitat, over relatively restricted areas, up to 140–190 pairs/km², but commonly densities lower, e.g. 6·25–15 pairs/km². Fate to some extent tied to that of burrow-nesting rodents, which supply nest-holes; thus species declines commensurately with declines in e.g. gerbil numbers owing to ploughing. Nonetheless, breeding range has expanded W since 1960 in apparent response to drier summers, with colonization of Crimea, Thrace, NE Greece, Aegean islands, Bulgaria and Romania; in Ukraine range has extended N following the expansion of little souslik (Citellus pygmaeus). Uncommon breeding visitor and resident in Israel (c. 70 pairs), but common to very common passage migrant and fairly common winter visitor; common breeder in upland steppe areas of Jordan. Very common in Mongolia, and common in N & NW China. Common to abundant throughout almost whole of winter quarters; greater frequency of records in NW Africa in recent years may reflect expansion of breeding range. Commonest wintering wheatear in many areas of UAE.