Lanius excubitor homeyeri Cabanis, 1873
Lanius excubitor homeyeri Cabanis, 1873
Common names: Great Grey Shrike, Northern Grey Shrike [En], Pie-grièche grise [Fr], Klapekster [Nl], Raubwürger [De], Averla maggiore [It],Alcaudón norteño [Es], Διπλοκεφαλάς [Gr], Büyük örümcek kuşu [Tu]
Livadia, SERRES ● Greece
Description: An adult great grey shrike is a medium-sized passerine about as large as a big thrush, measuring from 22 to 26 cm long. Wingspan can range from 30 to 36 cm.
The general colour of the upperparts is pearl grey, tinged brownish towards the east of its Eurasian range. The cheeks and chin as well as a thin and often hard-to-see stripe above the eye are white, and a deep black mask extends from the beak through the eye to the ear coverts; the area immediately above the beak is grey. The scapulars (shoulder feathers) are white, and the wings are black with a white bar made up by the bases of the primary remiges, continuing slightly offset onto the bases of the secondary remiges in some regions. The tail is black, long, and pointed at the tip; the outer rectrices have white outer vanes. The underparts are white, slightly tinged with grey. In particular the breast is usually darker and sometimes browner than the rest of the light underside, and may appear as an indistinct band between the lighter belly and white throat. The legs and feet are blackish.
Males and females are about the same size, and do not differ conspicuously in appearance except by direct comparison. In the female the underparts are greyer and are usually visibly barred greyish-brown, and the white wing and tail markings are characteristically less in extent (though this is rarely clearly visible except in flight). Fledged young birds are heavily tinged greyish-brown all over, with barring on the upperside and indistinct buffy-white markings. The tips of the tertiary remiges and the wing coverts are also buffy, with a black band in the latter. In the North American subspecies borealis, the fledglings are tinged quite brown indeed on upperside and wings, and have sharp and dark underside bars. In Eurasia, fledglings moult into a female-like plumage with the tertiary bars usually remaining in autumn. Across its range, the young acquire the adult plumage in their first spring.
There are at least two subspecies :
• L. e. excubitor Linnaeus – N, C & NE Europe (E from Scandinavia and C France) E to NW Siberia (lower R Ob), S to S Russia (Kazan area); non-breeding S Scandinavia, Britain and W & S France E to Asia Minor, Caucasus and Transcaspia – Medium grey above, pale grey hue below. Some white on primaries and sometimes secondaries.
• L. e. homeyeri – SE Europe (E Balkans, Bulgaria, S Romania, Ukraine E to foothills of S Urals) and SW Siberia (E to N foothills of Altai, including Naryn region); non-breeding SW & C Asia – Lighter grey than excubitor above, dull white below. More white on primaries and secondaries.
Biology: The great grey shrike eats small vertebrates and large invertebrates. To hunt, this bird perches on the topmost branch of a tree, telegraph pole or similar elevated spot in a characteristic upright stance some meters above ground. Alternatively, it may scan the grassland below from flight, essentially staying in one place during prolonged bouts of mainly hovering flight that may last up to 20 minutes. It will drop down in a light glide for terrestrial prey or swoop hawk-like on a flying insect. Small birds are sometimes caught in flight too.
Great grey shrikes breed during the summer, typically once per year. In exceptionally good conditions, they raise two broods a year, and if the first clutch is destroyed before hatching they are usually able to produce a second one. Copulation is typically initiated by the male bringing an attractive prey item to the female.
Nests are built in April or May more than 1 m above ground in trees. Presence of mistletoes or vines like common ivy (Hedera helix) on side branches near the trunk (where nests are preferentially built) will make a tree markedly more attractive. Fieldfares (Turdus pilaris) nesting in the vicinity will also increase the desirability of nest sites to great grey shrikes, which moreover often refuse to prey upon these thrushes' nestlings though the opportunity is there. Apparently, the two species are more efficient in spotting potential nest predators – in particular corvids – early on and mobbing them off cooperatively than either is on its own. The actual nesting site is chosen by the male; the courtship visits of the female are mainly to form and strengthen the pair bond. Also, though the partners build the nest together, the male collects most of the nesting material. The cup nest is constructed of coarse vegetable material – mainly large twigs and chunks of moss, though bits of fabric and rubbish may be added. The interior is lined with fine twigs and roots, lichen, hair and feathers.
Laying usually takes place in May. The clutch numbers three to nine eggs, typically around seven, with North American clutches tending to be larger on average than European ones. If a second clutch is produced in one breeding season, it is smaller than the first one. Incubation takes around 16 days but may be closer to three weeks for large clutches; it is generally done only by the female. While the male may briefly take over incubating, his task during this time is to provide food. The altricial nestlings hatch naked, blind and pink-skinned. As the nestlings grow, the female broods them, and later on assists in providing food. The young fledge after 2–3 weeks, typically in late June or early July; they become independent of their parents about 3–6 weeks later.
Habitat: The preferred habitat is generally open grassland, perhaps with shrubs interspersed, and adjacent lookout points. These are normally trees – at forest edges in much of the habitat, but single trees or small stands at the taiga-tundra border. In steppe, it will utilize any isolated perch, be it fence posts, power lines or rocks. In general, some 5–15 perching sites per hectare habitat seem to be required. It avoids low grassland with no lookouts and nesting opportunities (trees or large shrubs), as well as dense forest with no hunting ground. Apart from grassland, the birds will utilize a variety of hunting habitats, including bogs, clearings or non-industrially farmed fields.
Wikipedia, Great grey shrike