Western jackdaw

The western jackdaw (Coloeus monedula), also known as the Eurasian jackdaw, European jackdaw, or simply jackdaw, is a passerine bird in the crow family. Found across Europe, western Asia and North Africa, it is mostly resident, although northern and eastern populations migrate south in winter. Four subspecies are recognised, which mainly differ in the colouration of the plumage on the head and nape. Linnaeus first described it formally, giving it the name Corvus monedula. The common name derives from the word jack, denoting 'small', and daw, a less common synonym for 'jackdaw', and the native English name for the bird. Measuring 34–39 centimetres (13–15 in) in length, the western jackdaw is a black-plumaged bird with a grey nape and distinctive pale-grey irises. It is gregarious and vocal, living in small groups with a complex social structure in farmland, open woodland, on coastal cliffs, and in urban settings. Like its relatives, jackdaws are intelligent birds, and have been observed using tools. An omnivorous and opportunistic feeder, it eats a wide variety of plant material and invertebrates, as well as food waste from urban areas. Western jackdaws are monogamous and build simple nests of sticks in cavities in trees, cliffs, or buildings. About five pale blue or blue-green eggs with brown speckles are laid and incubated by the female. The young fledge in four to five weeks. The western jackdaw was one of the many species originally described by Carl Linnaeus in his 18th century work Systema Naturae. Owing to its supposed fondness for picking up coins, Linnaeus gave it the binomial name Corvus monedula, choosing the specific name mǒnēdŭla, which is derived from moneta, the Latin stem of the word 'money'. Jackdaws are sometimes placed in the genus Coloeus, from the Ancient Greek κολοιός (koloios) for jackdaw, though most subsequent works have retained the two jackdaw species in Corvus. The original Old English word ċēo (pronounced with initial ch) gave modern English 'chough'; Chaucer sometimes used this word to refer to the western jackdaw, as did Shakespeare in Hamlet although there has been debate about which species he was referring to. This onomatopoeic name, based on the western jackdaw's call, now refers to corvids of the genus Pyrrhocorax; the red-billed chough (Pyrrhocorax pyrrhocorax), formerly particularly common in Cornwall, became known initially as the 'Cornish chough' and then just the 'chough', the name transferring from one species to the other. The common name jackdaw first appeared in the 16th century, and is thought to be a compound of the forename Jack, used in animal names to signify a small form (e.g. jack snipe), and the archaic native English word daw. Formerly, western jackdaws were simply called 'daws'. The metallic chyak call may be the origin of the jack part of the common name, but this is not supported by the Oxford English Dictionary. Daw, first used for the bird in the 15th century, is held by the Oxford English Dictionary to be derived from the postulated Old English dawe, citing the cognates in Old High German tāha, Middle High German tāhe or tāchele, and modern German Dahle or Dohle, and dialectal Tach, Dähi, Däche and Dacha. Names in English dialects are numerous. Scottish and north English dialects have included ka or kae since the 14th century. The Midlands form of this word was co or coo. Caddow is potentially a compound of ka and dow, a variant of daw. Other dialectal or obsolete names include caddesse, cawdaw, caddy, chauk, college-bird, jackerdaw, jacko, ka-wattie, chimney-sweep bird (from their nesting propensities), and sea-crow (from the frequency with which they are found on coasts). It was also frequently known quasi-nominally as Jack. An archaic collective noun for a group of jackdaws is a 'clattering'. Another name for a flock is a 'train'. A study in 2000 found that the genetic distance between jackdaws and the other members of Corvus was greater than that within the rest of the genus. This led Pamela Rasmussen to reinstate the genus name Coloeus, created by Johann Kaup in 1829, in her Birds of South Asia (2005), a treatment also used in a 1982 systematic list in German by Hans Edmund Wolters. A study of corvid phylogeny undertaken in 2007 compared DNA sequences in the mitochondrial control region of several corvids. It found that the western jackdaw, and the closely related Daurian jackdaw (C. dauuricus) of eastern Russia and China, were basal to the core Corvus clade. The names Coloeus monedula and Coloeus dauuricus have since been adopted by the International Ornithological Congress in their official list. The two species of jackdaw have been reported to hybridise in the Altai Mountains, southern Siberia, and Mongolia. Analysis of the mitochondrial DNA of specimens of the two species from their core ranges show them to be genetically distinct.