The rook (''Corvus frugilegus'') is a member of the family
Corvidae
Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, jackdaws, jays, magpies, treepies, choughs, and nutcrackers. In colloquial English, they are known as the crow family or corvids. Cu ...
in the
passerine
A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by th ...
order of birds. It is found in the
Palearctic, its range extending from
Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and Swe ...
and
western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context.
The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
to eastern
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
. It is a large,
gregarious
Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies.
Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...
, black-feathered bird, distinguished from similar species by the whitish featherless area on the face. Rooks nest collectively in the tops of tall trees, often close to farms or villages, the groups of nests being known as
rookeries
A rookery is a colony of breeding animals, generally gregarious birds.
Coming from the nesting habits of rooks, the term is used for corvids and the breeding grounds of colony-forming seabirds, marine mammals ( true seals and sea lions), and ...
.
Rooks are mainly resident birds, but the northernmost populations may move southwards to avoid the harshest winter conditions. The birds form flocks in winter, often in the company of other ''
Corvus
''Corvus'' is a widely distributed genus of medium-sized to large birds in the family Corvidae. It includes species commonly known as crows, ravens and rooks. The species commonly encountered in Europe are the carrion crow, the hooded crow ...
'' species or
jackdaw
Jackdaws are two species of bird in the genus ''Coloeus'' closely related to, but generally smaller than, the crows and ravens (''Corvus''). ''Coloeus'' is sometimes treated as a subgenus of ''Corvus'', including by the IUCN.Madge & Burn (1994) ...
s. They return to their rookeries and breeding takes place in spring. They forage on arable land and pasture, probing the ground with their strong bills and feeding largely on grubs and soil-based invertebrates, but also consuming cereals and other plant material. Historically, farmers have accused the birds of damaging their crops, and have made efforts to drive them away or kill them. Like other corvids, they are intelligent birds with complex behavioural traits and an ability to solve simple problems.
Taxonomy and etymology
The rook was given its
binomial name by the Swedish naturalist
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in 1758 in his ''
Systema Naturae''. The binomial is from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
; ''Corvus'' means "raven", and ''frugilegus'' means for "fruit-gathering". It is derived from ''frux'' or ''frugis'', meaning "fruit", and ''legere'', meaning "to pick".
The English-language
common name ''rook'' is ultimately derived from the bird's harsh call.
Two subspecies are recognised; the western rook (''C. f. frugilegus'') ranges from western Europe to southern Russia and extreme northwestern China, while the eastern rook (''C. f. pastinator'') ranges from central Siberia and northern Mongolia eastwards across the rest of Asia.
Collective nouns
In linguistics, a collective noun is a word referring to a collection of things taken as a whole. Most collective nouns in everyday speech are not specific to one kind of thing. For example, the collective noun "group" can be applied to people (" ...
for rooks include ''building'', ''parliament'', ''clamour'' and ''storytelling''. Their colonial nesting behaviour gave rise to the term
rookery
A rookery is a colony of breeding animals, generally gregarious birds.
Coming from the nesting habits of rooks, the term is used for corvids and the breeding grounds of colony-forming seabirds, marine mammals ( true seals and sea lions), and ...
.
Description
The rook is a fairly large bird, at adult weight, in length and wingspan. It has black feathers that often show a blue or bluish-purple sheen in bright sunlight. The feathers on the head, neck and shoulders are particularly dense and silky. The legs and feet are generally black, the bill grey-black and the iris dark brown. In adults, a bare area of whitish skin in front of the eye and around the base of the bill is distinctive, and enables the rook to be distinguished from other members of the crow family. This bare patch gives the false impression that the bill is longer than it is and the head more domed. The feathering around the legs also appears shaggier and laxer than the similarly sized
carrion crow
The carrion crow (''Corvus corone'') is a passerine bird of the family Corvidae and the genus ''Corvus'' which is native to western Europe and the eastern Palearctic.
Taxonomy and systematics
The carrion crow was one of the many species or ...
, the only other member of its
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
with which the rook is likely to be confused.
[ Additionally, when seen in flight, the wings of a rook are proportionally longer and narrower than those of the carrion crow.] The average lifespan is six years.
The juvenile plumage is black with a slight greenish gloss, except for the hind neck, back and underparts, which are brownish-black. The juvenile is superficially similar to a young crow because it lacks the bare patch at the base of the bill, but it has a thinner beak and loses the facial feathers after about six months.[
Rook SJ1.JPG, At the Cafe, ]Marwell Zoo
Marwell Zoo is a zoo situated in Colden Common near Winchester, in the English county of Hampshire. It is owned and run by the registered charity Marwell Wildlife. The zoo is home to 1,208 animals of 149 species. The charity undertakes a ran ...
Corvus frugilegus-profile.jpg, At Uglich
Uglich ( rus, У́глич, p=ˈuɡlʲɪtɕ) is a historic town in Yaroslavl Oblast, Russia, located on the Volga River. Population:
History
The city was first documented in 1148 as ''Ugliche Pole'' (''Corner Field''). The town's name is though ...
, Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
Distribution and habitat
Rooks are resident in the British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...
and much of north
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography.
Etymology
The word ''north ...
and central Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
but vagrant
Vagrancy is the condition of homelessness without regular employment or income. Vagrants (also known as bums, vagabonds, rogues, tramps or drifters) usually live in poverty and support themselves by begging, scavenging, petty theft, temporar ...
to Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
and parts of Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and Swe ...
, where they typically live south of 60° latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
. They are found in habitats that ravens dislike, choosing open agricultural areas with pasture
Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or sw ...
or arable land
Arable land (from the la, arabilis, "able to be ploughed") is any land capable of being ploughed and used to grow crops.''Oxford English Dictionary'', "arable, ''adj''. and ''n.''" Oxford University Press (Oxford), 2013. Alternatively, for th ...
, as long as there are suitable tall trees for breeding. They generally avoid forests, swamps, marshes, heaths and moorland. They are in general lowland birds, with most rookeries found below , but where suitable feeding habitat exists, they may breed at or even higher. Rooks are often associated with human settlements, nesting near farms, villages and open towns, but not in large, heavily built-up areas.
The rook also occurs as an eastern species in Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
where it differs in being slightly smaller on average, and having a somewhat more fully feathered face. In the north of its range the species has a tendency to move south during autumn, and more southern populations are apt to range sporadically. The species has been introduced into New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, with several hundred birds being released there from 1862 to 1874. Although their range is very localized, the species is now regarded as an invasive pest and is the subject of active control by many local councils. This has wiped out the larger breeding colonies in New Zealand, and the remaining small groups have become more wary.
Behaviour and ecology
Rooks are highly gregarious birds and are generally seen in flocks of various sizes. Males and females pair-bond for life and pairs stay together within flocks. In the evening, the birds often congregate at their rookery before moving off to their chosen communal roosting
Communal roosting is an animal behavior where a group of individuals, typically of the same species, congregate in an area for a few hours based on an external signal and will return to the same site with the reappearance of the signal. Environment ...
site. Flocks increase in size in autumn with different groups amalgamating and birds congregating at dusk before roosting, often in very large numbers and in the company of jackdaws. Roosting usually takes place in woodland or plantations, but a small minority of birds may continue to roost at their rookery all winter, and adult males may roost collectively somewhere nearby. The birds move off promptly in the morning, dispersing for distances of up to .[
Large groups of rooks (in breeding colonies or night roost sites) can contribute to changes in soil properties. The amount of ornithogenic material in these soils is very high.
Foraging mostly takes place on the ground, with the birds striding about, or occasionally hopping, and probing the soil with their powerful beaks. Flight is direct, with regular wingbeats and little gliding while in purposeful flight; in contrast, the birds may glide more extensively when wheeling about in leisure flight near the rookery. In the autumn, flocks sometimes perform spectacular aerial group flights, including synchronised movements and individual antics such as dives, tumbles and rolls.][
]
Diet and feeding
Examination of stomach contents show that about 60% of the diet is vegetable matter and the rest is of animal origin. Vegetable foods include cereals, potato
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern Unit ...
es, roots, fruit, acorns, berries and seeds while the animal part is predominantly earthworm
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. T ...
s and insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
e, which the bird finds by probing the ground with its strong bill. It also eats beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s, spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s, millipede
Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...
s, slugs, snail
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ...
s, small mammals, small bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s, their eggs and young, and occasionally carrion.[
In ]urban
Urban means "related to a city". In that sense, the term may refer to:
* Urban area, geographical area distinct from rural areas
* Urban culture, the culture of towns and cities
Urban may also refer to:
General
* Urban (name), a list of people ...
sites, human food scraps are taken from rubbish
Rubbish may refer to:
*Waste
*Garbage
* ''Rubbish'' (magazine), a fashion magazine
* ''Rubbish'' (radio series), a British radio series
*"Rubbish", a song by Carter the Unstoppable Sex Machine
*An adjective which is colloquially used in British En ...
dumps and streets, usually in the early hours or at dusk when it is relatively quiet. Like other corvids, rooks will sometimes favour sites with a high level of human interaction, and can often be found scavenging for food in tourist areas or pecking open garbage sacks.[ Rooks have even been trained to pick up litter in a theme park in France.
]
Courtship
The male usually initiates courtship, on the ground or in a tree, by bowing several times to the female with drooping wings, at the same time cawing and fanning his tail. The female may respond by crouching down, arching her back and quivering her wings slightly, or she may take the initiative by lowering her head and wings and erecting her partially spread tail over her back.[ Further similar displays are often followed by begging behaviour by the female and by the male presenting her with food, before coition takes place on the nest. At this stage, nearby male rooks often ]mob
Mob or MOB may refer to:
Behavioral phenomena
* Crowd
* Smart mob, a temporary self-structuring social organization, coordinated through telecommunication
Crime and law enforcement
* American Mafia, also known as the Mob
* Irish Mob, a US crimin ...
or attack the mating pair, and in the ensuing struggle, any male that finds himself on top of the female will attempt to copulate with her. She terminates these unwanted advances by exiting the nest and perching nearby. A mated pair of rooks will often fondle each other's bills, and this behaviour is also sometimes seen in autumn.[
]
Breeding
Nesting in a rookery is always colonial
Colonial or The Colonial may refer to:
* Colonial, of, relating to, or characteristic of a colony or colony (biology)
Architecture
* American colonial architecture
* French Colonial
* Spanish Colonial architecture
Automobiles
* Colonial (1920 au ...
, usually in the very tops of large trees, often on the remnants of the previous year's nest. In hilly regions, rooks may nest in smaller trees or bushes, and exceptionally on chimneys or church spires. Both sexes participate in nest-building, with the male finding most of the materials and the female putting them in place. The nest is cup-shaped and composed of sticks, consolidated with earth and lined with grasses, moss, roots, dead leaves and straw.[ Small branches and twigs are broken off trees, though as many are likely to be stolen from nearby nests as are collected direct, and the lining material is also often taken from other nests.][
Eggs are usually three to five in number (sometimes six and occasionally seven) and may be laid by the end of March or early April in Britain, but in the harsher conditions of eastern Europe and Russia, it may be early May before the clutch is completed.] The background colour is bluish-green to greyish-green but this is almost completely obscured by the heavy blotching of ashy grey and brown. The eggs average in size.[ They are incubated for 16–18 days, almost entirely by the female who is fed by the male. After hatching, the male brings food to the nest while the female broods the young. After ten days, she joins the male in bringing food, which is carried in a throat pouch. The young are fledged by the 32nd or 33rd day but continue to be fed by the parents for some time thereafter. There is normally a single clutch each year, but there are records of birds attempting to breed in the autumn.][
In autumn, the young birds of the summer collect into large flocks together with unpaired birds of previous seasons, often in company with jackdaws. It is during this time of year that spectacular aerial displays are performed by the birds. The species is monogamous, with the adults forming long-term ]pair bond
In biology, a pair bond is the strong affinity that develops in some species between a mating pair, often leading to the production and rearing of offspring and potentially a lifelong bond. Pair-bonding is a term coined in the 1940s that is freque ...
s. Partners often support each other in agonistic encounters and a bird may return to its partner after a quarrel where bill twining, an affiliative behaviour, may take place.
Voice
The call is usually described as ''caw'' or ''kaah'', and is somewhat similar to that of the carrion crow, but less raucous. It is variable in pitch and has several variants, used in different situations. The call is given both in flight and while perched, at which time the bird fans its tail and bows while making each caw. Calls in flight are usually given singly, in contrast to the carrion crow's, which are in groups of three or four. Other sounds are made around the rookery; a high-pitched squawk, a "burring" sound and a semi-chirruping call. Solitary birds occasionally "sing", apparently to themselves, uttering strange clicks, wheezes and human-like notes; the song has been described as a "base or guttural reproduction of the varied and spluttering song" of starling
Starlings are small to medium-sized passerine birds in the family Sturnidae. The Sturnidae are named for the genus '' Sturnus'', which in turn comes from the Latin word for starling, ''sturnus''. Many Asian species, particularly the larger ones, ...
s.[
]
Intelligence
Although outside of captivity rooks have not shown probable tool-use, captive rooks have shown the ability to use and understand puzzles. One of the most commonly tested puzzles is the Trap-Tube Problem. Rooks learned how to pull their reward out of the tube while avoiding a trap on one side.
In captivity, when confronted with problems, rooks have been documented as one of several species of birds capable of using tools as well as modifying tools to meet their needs. Rooks learned that if they push a stone off a ledge into a tube, they will get food. The rooks then discovered they could find and bring a stone and carry it to the tube if no stone was there already. They also used sticks and wire, and figured out how to bend a wire into a hook to reach an item. Rooks also understood the notion of water levels. When given stones and a tube full of water with a reward floating, they not only understood that they needed to use the stones but also the best stone to use.
In one set of experiments, rooks managed to knock a reward off a platform by rolling a stone down a tube toward the base of the platform. Rooks also seemed to understand the idea that a heavier stone will be more likely to knock the platform over. In this same test, rooks showed they understood that they needed to pick a stone of a shape that would roll easily.[
Rooks also show the ability to work together to receive a reward. In order to receive a reward, multiple rooks had to pull strings along the lid of a box in order for it to move and them to reach the reward. Rooks seem to have no preference regarding working as a group comparative to working singly.
They also seem to have a notion of gravity, comparable to a six-month-old baby and exceeding the abilities of chimpanzees. Although they do not use tools in the wild, research studies have demonstrated that rooks can do so in cognition tests where tools are required, and can rival, and in some circumstances outperform, chimpanzees.
]
Relationship with humans
Farmers have observed rooks in their fields and thought of them as vermin. After a series of poor harvests in the early 1500s, introduced a Vermin Act in 1532 "ordeyned to dystroye Choughes (i.e. jackdaws), Crowes and Rokes" to protect grain crops from their predations. This act was only enforced in piecemeal fashion, but passed the ''Act for the Preservation of Grayne'' in 1566 that was taken up with more vigour and large numbers of birds were culled.
Francis Willughby
Francis Willughby (sometimes spelt Willoughby, la, Franciscus Willughbeius) FRS (22 November 1635 – 3 July 1672) was an English ornithologist and ichthyologist, and an early student of linguistics and games.
He was born and raised at ...
mentions rooks in his ''Ornithology'' (1678): "These birds are noisome to corn and grain: so that the husbandmen are forced to employ children, with hooting and crackers, and rattles of metal, and, finally by throwing of stones, to scare them away." He also mentions scarecrow
A scarecrow is a decoy or mannequin, often in the shape of a human. Humanoid scarecrows are usually dressed in old clothes and placed in open fields to discourage birds from disturbing and feeding on recently cast seed and growing crops.Lesley ...
s "placed up and down the fields, and dressed up in a country habit, which the birds taking for countrymen dare not come near the grounds where they stand".[ It was some time before more observant naturalists like John Jenner Weir and ]Thomas Pennant
Thomas Pennant (14 June OS 172616 December 1798) was a Welsh naturalist, traveller, writer and antiquarian. He was born and lived his whole life at his family estate, Downing Hall near Whitford, Flintshire, in Wales.
As a naturalist he h ...
appreciated that in consuming ground-based pests, the rooks were doing more good than harm.[
Rookeries were often perceived as nuisances in rural Britain, and it was previously the practice to hold rook shoots where the juvenile birds, known as "branchers", were shot before they were able to fly. These events were both a social occasion and a source of food (the rook becomes inedible once mature) as rook and rabbit pie was considered a delicacy.]
Rooks have a wide distribution and large total population. The main threats they face are from changes in agricultural land use, the application of seed dressings and pesticides, and persecution through shooting. Although total numbers of birds may be declining slightly across the range, this is not at so rapid a rate as to cause concern, and the International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...
has assessed the bird's conservation status as being of "least concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
".
References
External links
*
Rook videos, photos & sounds
on the Internet Bird Collection
{{Good article
Corvus
Birds of Eurasia
Birds of New Zealand
Birds described in 1758
Taxa named by Carl Linnaeus