Sunday, 18 February 2018

Great grey shrike (Lanius excubitor) - Διπλοκεφαλάς - Cyprus

The bird is the nominate Great Grey Shrike excubitor . This is the first record of the nominate Great Grey Shrike in Cyprus
The great grey shrike, northern grey shrike, or northern shrike (Lanius excubitor) is a large songbird species in the shrike family (Laniidae). It forms a superspecies with its parapatric southern relatives, the southern grey shrike (L. meridionalis), the Chinese grey shrike (L. sphenocerus) and the loggerhead shrike (L. ludovicianus). Within the great grey shrike species itself, there are two subspecies. Males and females are similar in plumage, pearly grey above with a black eye-mask and white underparts.

Breeding takes place generally north of 50° northern latitude in northern Europe and Asia. Most populations migrate south in winter to temperate regions. The great grey shrike is carnivorous, with rodents making up over half its diet.

The great grey shrike occurs throughout most temperate and subarctic regions of the Northern Hemisphere. Generally, its breeding range is limited to areas north of 50° northern latitude in Eurasia. In the high mountains of the Altai-Tian Shan region, it ranges south perhaps as far as 42° northern latitude. Its northern limit is generally 70° northern latitude. It is only found as a vagrant in Iceland, the British Isles, the Mediterranean region (excluding the Iberian Peninsula and perhaps Romania but including Cyprus), and Korea. There do not appear to be breeding records from the entire Kamchatka Peninsula; in Switzerland, the present day Czech Republic and southern Germany small populations were found in the mid-20th century but have declined or even disappeared since then.

Except for the subspecies bianchii which is largely all-year resident, and subspecies excubitor in the temperate European parts of its range with their mild maritime climate, the species is a short-distance migrant. The migrations are triggered by scarcity of food and therefore, according to prey population levels, the winter range might little extend south beyond the breeding range, or be entirely parapatric to it. The populations of the Central Asian mountains mostly migrate downslope rather than southwards. Females are more prone to migration than males; they do not appear to migrate, on average, longer or shorter distances than males, and consequently are the dominant sex in many parts of the winter range. Birds leave for winter quarters a more or less short time after breeding – July to October, with most birds staying to September – and return to nest mainly in March/April, but some only arrive in May. In recent decades, the number of birds remaining on the breeding grounds all year has been noted to increase e.g. in Fennoscandia, whereas for example borealis seems to be as rare a winter visitor in northern Ohio as it was a century ago.

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. Breeding birds appear to have different microhabitat desires, but little detail is known yet

Like other Laniidae, the Great Grey Shrike has highly specialized feeding behaviour, unique among passerines. Its scientific name means “sentinel butcher”, referring to this behaviour.
It hunts by watching for prey from high, exposed perches. Once it is detected, the bird drops down on to it after a brief hovering. These prey, both large insects and small vertebrates, are killed with the strong, hooked bill. Then, the victim is impaled on thorns or barbed wire used as meat hooks. The Great Grey Shrike kills a large variety of prey, including small mammals and birds, various small vertebrates and invertebrates and large insects.
The Great Grey Shrike is not currently globally threatened throughout the wide range in Northern Hemisphere, in North America and Eurasia. Seven subspecies share this large territory.

Length: 24-25 cm
Weight: 48-80 g

The Great Grey Shrike adult has pale grey upperparts with variable bluish wash, including top of head and nape to lower back. Rump and uppertail-coverts are pale grey too, but slightly paler. The upperwing is black with white bar across primary bases, and a smaller white patch at secondary bases. Flight feathers and tertials have white tips. The scapulars are white. The long, graduated tail is black with white outer rectrices. 
The underparts are white, including chin and throat. The bird may have a weak pink tinge on breast in fresh plumage.

On the head, we can see a narrow black mask extending from bill base through lores and eyes to rear of ear-coverts. There is a very narrow, white supercilium, sometimes absent.
The strong, hooked bill is black. The eyes are dark brown. Legs and feet are blackish.

Male and female are similar, but males have more contrasting markings than females. The female may show a weak barring on the breast. She is usually slightly duller.

The juvenile is usually browner than adults, with indistinct vermiculations on upperparts and underparts. In autumn, it resembles adult female, but it retains some weak barring on breast and flanks, and pale-edged greater coverts.

The Great Grey Shrike has seven subspecies that differ in plumage and body size.
L.e. borealis breeds in NE Canada. It is present in S Canada and most of W and C USA outside breeding season.
This race is similar to nominate with more conspicuous white supercilium, less white on upperwings and greyer underparts densely vermiculated dark. The juvenile is darker and browner than nominate. 

L.e. excubitor (described above) breeds in N, C and NE Europe, E to NW Siberia. Present outside breeding season in S Scandinavia, Britain, W and S France, E to Asia Minor, Caucasus and Transcaspia. 

L.e. sibiricus breeds in C and E Siberia, E to Kolyma Basin, Anadyrland and Chukotsk Peninsula, S to L Baikal, N Mongolia and SE Russia. It winters in SC Siberia, Mongolia, NE China and Ussuriland.
This race has ochre tinge above and some vermiculations below.

L.e. homeyeri breeds in SE Europe and SW Siberia. It winters in SW and C Asia.
This one is paler than nominate, with mostly whitish rump and uppertail-coverts. The supercilium is more conspicuous. There is more extent of white in wings and tail.

L.e. mollis breeds in CS Russia and NW Mongolia. Outside breeding season, it occurs in N China too.
This race is darker than “sibiricus” and has smaller white wing patch, buffer underparts with more vermiculations.

L.e. funereus occurs in E Kazakhstan and S Tien Shan.
This one is the largest. It is darker than “mollis” with more heavily vermiculated underparts.

L.e. bianchii breeds on Sakhalin Island and Kuril Islands. It winters in N Japan (Hokkaido).
This race is small, similar to “sibiricus” but paler and greyer, and less vermiculated below. 

The Great Grey Shrike frequents various types of open areas where it breeds, from semi-desert to farmland, heathland, scrub, bogs, and partly forested tundra and coastal dunes, all with scattered trees, scrub and bushes used as perches from which they hunt.
Outside breeding season, it can be found in similar habitats, but with more meadows.

Photos and video alaminos 18/2/2018 by George Konstantinou

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