|Copyright: Anil Purohit (purohit)
|Date Taken: 2009-01-20|
|Camera: Nikon D 50, Nikkor 70-300 G|
|Exposure: f/7.1, 1/640 seconds|
|More Photo Info: [view]|
|Photo Version: Original Version|
|Date Submitted: 2010-09-29 0:58|
|[Note Guidelines] Photographer's Note|
|This Shot taken at Tal Chhapar Sanctuary.|
Great Grey Shrike
The Great Grey Shrike or Northern Grey 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 nine 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, and in North America (where it known as the Northern Shrike) north of 55° northern latitude in Canada and Alaska. Most populations migrate south in winter to temperate regions. The Great Grey Shrike is carnivorous, with rodents making up over half its diet.
Taxonomy and systematics
The scientific name of the Great Grey Shrike literally means "sentinel butcher": Lanius is the Latin term for a butcher, while excubitor is Latin for a watchman or sentinel. This refers to the birds' two most conspicuous behaviours – storing food animals by impaling them on thorns, and using exposed tree-tops or poles to watch the surrounding area for possible prey. Use of the former by Conrad Gessner established the quasi-scientific term lanius for the shrikes. Linnaeus chose his specific name because the species "observes approaching hawks and announces [the presence] of songbirds" as he put it. This habit was also put to use in falconry, as fancifully recorded by William Yarrell later. The species was first scientifically described by Carl Linnaeus in his 1758 edition of Systema Naturae under the current scientific name. His description is L[anius] cauda cuneiformi lateribus alba, dorso cano, alis nigris macula alba – "a shrike with a wedge-shaped white-bordered tail, back grey, wings black with white spot". At that time, none of the other grey shrikes – including the Lesser Grey Shrike (L. minor), for which the description of the tail pattern is incorrect and which some authors already recognized as distinct – were considered separate species by Linnaeus, but that was to change soon. Linnaeus' binomial name replaced the cumbersome and confusing descriptive names of the earlier naturalist books he gives as his sources: in his own Fauna Svecica he named it ampelis caerulescens, alis caudaque nigricantibus ("light-blue waxwing, wings and tail blackish"), while it is called pica cinerea sive lanius major ("ash-grey magpie or greater shrike") by Johann Leonhard Frisch, who in his splendid colour plate confused male and female. But most authors cited by Linnaeus – Eleazar Albin, Ulisse Aldrovandi, John Ray and Francis Willughby – called it lanius cinereus major or similar, which is a near-literal equivalent of the common name "Great Grey Shrike". The type locality of Linnaeus is simply given as Europa ("Europe").
As remarked above, the Great Grey Shrike has apparently become extinct as a breeding bird in Switzerland and Czechia. Overall, its stocks seem to be declining in the European part of its range since the 1970s. In North America, the populations seem to have been stable by contrast, except in the east. The 11-year sunspot cycle does not seem to be closely linked to these fluctuations, and probably neither to the eight-year cycle recorded in subspecies borealis (and perhaps present in others). Rather, the increase and decline seem to be reactions to changing land use, with an increase as the number of agricultural workers declined after World War II and land fell fallow, declining again when land consolidation (see e.g. Flurbereinigung) had seriously depleted the number of hedgerows and similar elevated growth formerly common amidst the agricultural landscape. For such a predatory bird, the indiscriminate use of pesticides (which will accumulate in adult carnivores and inhibit breeding success) around the 1960s probably had a detrimental influence on stocks too. Altogether, the Great Grey Shrike is common and widespread and not considered a threatened species by the IUCN (though they still include L. meridionalis in L. excubitor). Wherever it occurs, its numbers are usually many hundreds or even thousands per country. Its stronghold is the region around Sweden, where at least almost 20,000, perhaps as many as 50,000 were believed to live in the late 20th century. However, in some countries it is not robustly established; in Estonia only a few hundred are found, with less than 200 in Belgium and some more or less than 100 in Latvia and Lithuania, respectively. The few dozen in the Netherlands and the 10 birds or so in Denmark might disappear because of a few years of adverse circumstances. By contrast, in Luxembourg plentiful high-quality habitat is found; though the number of Great Grey Shrikes in this tiny country is necessarily limited, the average population density there is 25 times as high as in Lithuania.
- From Wikipedia
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