Just before dusk during the short days of winter in virtually any farmed area across much of western and central Europe large wheeling flocks of rooks (Corvus frugilegus) gather in the gloom in the tops of tall trees in traditional pre-roosts. The air is filled with their harsh ‘graah’ calls, that can be almost deafening at large roosting sites. They gather in the dusk at the pre-roost before finally going to their main roost, often alongside their corvid cousins the Eurasian Jackdaw (Corvus monedula) and Daurian Jackdaw (Corvus dauuricus).
Everything You Need To Know About The Rook:
Often overlooked, in favor of its showier relatives, the humble rook is among the most intelligent of all corvids, with a long history of interaction with people across the Eurasian landmass from Ireland to Japan.
This is perhaps one of the most gregarious, sociable and intelligent of all corvids, and over the years has managed to adapt to the modern agricultural environment and is increasingly adapting to suburban and even urban environments like its other corvid brethren such as the Magpie (Pica pica) and Carrion Crow (Corvus corone), although few nest in urban environments.
- Lifespan – Average of 7 years, but can live up to 20 years or more.
- Weight – 430 grams (15 oz)
- Length – 45 cm (17.7 inches)
- Wingspan – 90 cm (35.4 inches)
- Family – Corvidae (Crows, Jays, Magpies, Chough and Treepies)
1. Etymology, Colloquial And Collective Names
The rook was given the latin name of Corvus frugilegus, by Carl Linnaeus in his Systema Naturae in 1758. The name is formed from Corvus meaning Raven and frugilegus meaning fruit-picking. The latter part of the name originates from the latin frugis or frux, meaning fruit and legere meaning to pick. Although not renowned for its fruit-picking abilities, it is likely that they would eat fruit from orchards or various berries as they are omnivores with a varied diet.
The English name rook has its origins in the raucous calls of the bird and dates back to the mediaeval period. Indeed, the Gaelic roc means croak, and in Sanskrit kruc ” means to cry out. The Old English name was hroc, which itself perhaps originates from the proto-German khrokaz. The bird is similarly called hrokr in Old Norse, roek in, Dutch and roka in Middle Swedish. The Scottish name is Craa, rather similarly derives from the raucous call as well.
Interestingly rook also came to be used as a disparaging term for a person from the 16th century onwards, perhaps related to their habit of stealing nesting materials from one another. Their reputation as intelligent, scheming birds may also have been instrumental in the word being as a verb and noun meaning to cheat or defraud or a cheat,” especially at cards, dice or other games from the 1570’s onwards.
Being such an obviously sociable bird, several names have been used for gatherings of rook, the most well-known being a parliament, but also a story-telling and building of rooks.
The term ‘Rookery’ refers to a colony of rooks, but over time this term has been applied to large gregarious colonies of various bird species, pinnipeds (seals and sea lions) and even turtles.
In the 19th century the term was also used to describe large overcrowded slum dwellings in the industrial heartlands of Britain, where the houses. Although no longer used as the slums have gone, the name ‘The Rookery’ lingers on for dwellings in rural areas of the United Kingdom.
2. History, Myth And Culture
The rook has appeared in English literature since the time of Chaucer in the 15th Century and his poem ‘The Parliament of Fowles’, and has been immortalized by writers ever since, although the similarity of the crow to the rook were often confused in early literature, whether it be Shakespeare who writes ‘light thickens, as well as the crow makes side to the rooky wood’, or Tennyson, with his ‘many-wintered crow leading the clanging rookery home’.
From the medieval period or perhaps even earlier the idea of a gathering of rooks being called a Parliament came from the folk myth that the birds would hold a solemn meeting to decide the fate of any rook found to have stolen twigs from other rooks neighboring nests to strengthen their own, which could even result in the death by execution of the culprit to punish the misdeed to maintain the morals of the community. This belief has persisted into modern times and as yet it is still unclear why sometimes birds are seen to gather in circles, often surrounding two birds in the center of the circle.
The rook has through the centuries been considered a bird of both good and bad omen. It was believed that rooks would only build their rookeries near houses where the inhabitants were of a kind and generous disposition. The noble men of England were happy to have a rookery close to their castles and manor houses, because rooks were regarded as “fowls of good omen.” Moreover no one was permitted to kill them, under severe penalties unlike many other pest species.
However, rooks deserting a rookery was said to foretell the downfall of the family on whose property it is. There was also a notion that when rooks haunt a town or village “mortality is supposed to await its inhabitants, and if they feed in the street it shows that a storm is at hand. The rook was mentioned as an ominous bird in Shakespeare’s “Macbeth,” (Act 3 Scene 4) as Macbeth sees them as an augur of bad omen and may well reveal the secret of his murdering Banquo. Indeed, in the north of England it was believed that should a rook enter a house alive or dead it would bring dire misfortune upon the inhabitants.
In later literature there was a more modern appreciation of a bird that had for so long been considered a pest, and at times an omen of bad portent. Sylvia Plath in her poem ‘Black Rook in Rainy Weather’ spoke of the beauty of a seemingly mundane bird:
“I only know that a rook
Ordering its black feathers can so shine
As to seize my senses, haul
My eyelids up, and grant
A brief respite from fear
Of total neutrality.”
Perhaps more than anyone the 19th century French poet Arthur Rimbaud captured the beauty, yet sinister quality of rooks gathering and flying on their noisy flocks before dusk:
“In your thousands, over the fields of France
where the day before yesterday’s dead are sleeping,
wheel in the wintertime, won’t you,
so that each traveler may remember!
Be, then, the one who calls men to duty,
O funeral black bird of ours!
But, ye saints of the sky,
at the oak tree top, the masthead lost in the enchanted twilight “
Moreover, some common phrases like ‘As the crow flies’, perhaps come from that tendency to blend the two species together. In reality it is the rook that flies long distances in a straight line to its roost spot, a journey unlikely to be taken by the less sociable Carrion Crow, which rarely roosts far from its home range or in large numbers and so doesn’t need to fly long distances.
Rooks are such an indelible part of the landscape in the farming areas of the United Kingdom that many landmarks, farms and even villages bear their name. Over 170 locations on ordnance survey maps begin with the name ‘Rook’ and include Rook Hill, Rook’s Nest and Rookswoods. There are some 80 Rookery farms and even 14 villages with ‘Rook’ in the name. Often these rookeries have existed in the same locations for hundreds of years.
Similar in size and shape to the Carrion Crow, the juvenile especially can be easily confused with that species, as it lacks the grey bill and bare skin on the lores and neck of the adult. The east Asian subspecies ‘pastinator’ differs in having a lesser amount or no bare skin and averages smaller than the European and west Asian subspecies ‘frugilegus’.
The adult rook is largely black apart from the bill and a bare area of pale grey skin on the lores (in front of the eye) and on the neck. This very distinctive feature separates the adults easily from other black corvids such as Raven, Jackdaw or Carrion Crow. This adaption helps with searching for insect prey when probing in wet earth. The forehead is flat, the nape short, with a more peaked crown than other corvid species.
The plumage is glossy black feathers that can appear blue or bluish-purple sheen in bright sunshine. The feathers on the head, neck and shoulders are particularly dense and silky. The legs and feet are black, the bill grey-black and the iris dark brown. The feathering around the legs look rather like a ruffled pair of baggy shorts with feathers hanging down, unlike the similarly-sized Carrion Crow.
In flight, the wings of the rook appear longer and the wing tips narrower than those of the carrion crow, and the wingbeats are faster and deeper, with the tail more rounded with a wedge-shaped tail tip.
The juvenile rook is superficially similar to Carrion Crow, as it lacks the grey bill and pale grey skin around the eye for the first year, the bare skin only developing from February to May of the second year. The bill is subtly different to Carrion Crow having a straighter culmen (upper mandible) and more pointed tip.
The plumage is largely black with a greenish sheen, with the nape, mantle and underparts, appearing brownish-black. The easiest way to distinguish juveniles from Carrion Crows are their rather hoarse noisy croaking calls.
The general call is a hoarse, croak, often described as ‘geeah’ or ‘graah’. They also have a series of bubbling soft calls used during pair bonding. However, the 19th century ornithologist Edward Selous found they had up to 30 rather subtly different calls, forming a more harmonious and lyrical soundscape than the harsh tones of the Carrion Crow. They are very vocal at dusk around the pre-roost or when flying to roost and at colonies during the spring and summer.
4. Distribution, Taxonomy, Population And Status
The rook can be found across much of Europe, mainly western, central and Eastern Europe, as well as southern Scandinavia and through central Asia, as far as Eastern Russia, China and Japan. Vagrants have been recorded as far north as Greenland, Iceland, and south to Algeria, as well as Kuwait, Lebanon and Taiwan. Although largely resident, the more northerly populations migrate south and range quite widely in search of food, some crossing the sea to winter in Japan and the UK.
Rooks were also introduced into New Zealand by early settlers and at their peak numbered up to 30,000 mainly on the North island.
There are two races of rook, the western rook (Corvus f. frugilegus) ranges from western Europe to southern Russia and extreme northwestern China, while the eastern rook (Corvus f.pastinator) ranges from central Siberia and northern Mongolia eastwards across the rest of Asia.
The rook is still a common bird across much of its range and therefore considered of least concern by the IUCN, the global population is estimated between 54 and 95 million birds.
The rook is very tied to man-made habitats, foraging in pasture, along roadsides and farmland areas. In some parts of their range, they also nest and forage in riparian areas (near rivers and streams) as the soft soil is perfect for their invertebrate prey.
They are colonial nesters, and the colonies known as rookeries are usually built in the tops of tall trees, often in small open woods or in hedgerows or trees lining avenues and even in large rural gardens.
They have also rarely been recorded nesting in bushes and even on the ground at upper elevations and although not usually associated with nesting on man-made structures, they were observed in the 19th century trying to nest on the weather vanes atop the white tower in the tower of London and sometimes use the top of church spires or chimneys.
In the winter they can also be found foraging in coastal areas on mudflats or along beaches. However, they are increasingly moving into suburban and urban areas in some parts of their range, foraging from bird tables and around litter bins, on streets and refuse tips.
6. Diet And Feeding Habits
Rooks are omnivorous, eating both plant and animal matter and enormously adaptable in their feeding habits. They are opportunistic feeders and will eat just about anything that they can easily catch or forage and hence have a very varied diet.
Rooks have very sensitive bills, served by two nerves that run down between the eyes to the upper mandible, which allow them to probe and dig to find prey items such as cockchafer grubs without seeing them. Just like their corvid cousin the Eurasian Jay they have also been known to cache acorns and other food items burying them in a favored spot, often flying up to three kilometers (two miles) to do so. They have also been seen to break open mussels on rocks and will peck at and turn over animal droppings in search of beetles and other invertebrates.
Their favored prey item is invertebrates such as earthworms, locusts, grasshoppers, spiders, slugs, snails and insect larvae such as leatherjackets. However, they also feed on cereals, potatoes, roots, acorns, seeds, berries, nuts, and fruits if available and will eat a range of carrion, such as small birds, their eggs and chicks, as well as small reptiles and mammals.
In urban and suburban areas, they will also feed on human food waste taken from rubbish bins and refuse tips, grain from bird tables and invertebrates or carrion even on the sides of busy roads.
7. Behavior And Breeding
Perhaps the most gregarious of all corvids, at least in Europe and Asia, they can gather in massive flocks to feed and roost during the non-breeding season. Roost of up to 65,000 birds have been counted and they can travel considerable distances, sometimes up to 27 miles (45km) to reach a roost from the feeding areas. They often roost with other corvid species such as Magpie, Raven and Jackdaws.
They usually fly on rather stiff wings in direct flight, but are really very agile and will also soar with other corvids such as Jackdaws and enjoy aerial play, falling and tumbling in high winds or over hillsides. If a predator such as a Buzzard approaches a colony the birds in the rookery will noisily gather together to harry it and chase it away.
The rookeries are mostly abandoned in winter, though they may be used as a pre-roost. At the beginning of the breeding season, they return to the rookeries.
They nest in loose colonies, with anywhere from small colonies of 50 or less nests to massive conglomerations of up to 10,000 nests. The breeding season begins in late February as they begin to pair up and rebuild their large robust nests. The nest is usually towards the top of a tree, with a very bulky outer layer of branches, twigs and leaves and inside a deep cup made up of roots and grasses. Usually rooks nest in single species colonies, but in the Volga delta they nest side by side with Cormorants, Glossy Ibis and herons.
They begin by rebuilding the nest, foraging for branches and twigs and are well-known to steal twigs from other nests within the colonies. It was believed that other rooks within the colony would punish those on the edge of a colony by dismantling their nests, but this is more likely to be the more mature successful birds in the center of the colony taking nesting materials from failed young breeders at the peripheries.
Once they have completed the nest, and before laying the eggs, the male will begin to feed the female, with Gilbert White describing the female receiving “the bounty with a fondling tremulous voice and fluttering wings, and all the little blandishments that are expressed by the young, while in a helpless state”, with the behavior continuing through to hatching.
The male rook doesn’t really have a song as such, but ‘sings’ from an exposed perch, with a wide variety of cawing, clicking and gurgling sounds while moving its head up and down and fanning its tail during the display. In response the female will arch her back, lower her head, quiver her wings and raising her tail over her back.
These displays are sometimes followed by begging by the female while the male presents her with food, before finally mating. Other nearby male rooks will try their luck and sneak in a secret bit of mating by mobbing the pair and pushing the paired male of the female. The male also performs a rather odd stiff-winged and deeply flapping flight over the rookery. Mated pairs also indulge in mutual bill fondling, during the breeding season and even autumn.
Egg-laying can start as early as the end of February in Britain, though in central Europe it is usually early April, mid-April in Russia and early may in Kazakhstan. They usually lay 3-5 eggs (exceptionally up to 7), which take 16-18 days to incubate. The female usually incubates, though the male will sometimes briefly cover the eggs. Initially it is the male that feeds the young for the first 10 days or so, until the young are large enough for the female to help with feeding. Fledging takes around 32-33 days, and the young will leave the nest and then roost in nearby trees. The freshly fledged young spend several weeks with the parents until independent.
8. Predators And Threats
Adult rooks have few natural predators and forming large flocks help them to fend off any would-be predators to some extent. I have observed Common Buzzard working together at rookeries to take eggs or chicks with one bird distracting the adults, while another goes into the nest and takes the eggs or chicks.
Strangely rooks will even tolerate some raptors nesting within the rookery, with Kestrel, Lesser Kestrel, Long-eared Owl and even Osprey having been recorded as nesting in empty nests within colonies. In fact, Red-footed Falcon and Amur Falcon heavily rely on rookeries and will nest within the colony, returning to breed once the rooks are actively nesting and will even evict eggs and chicks if empty nests are in short supply.
The main threat to rooks comes from man, either through the indiscriminate shooting of them or the use of poisons, larsen traps and accidental poisoning through overuse of pesticides.
9. Interactions With Humans
The rook, alongside the Carrion Crow has for centuries been considered by farmers to cause considerable damage to cereal crops. Although perhaps this is to some extent unwarranted, as they actually eat many invertebrate species that would otherwise potentially cause damage to crops, they are still considered a major pest to this day and so are shot and trapped or deterred from cereal fields.
The persecution of rooks can be traced back to at least 1424 in Scotland where laws were introduced ordering landowners to prevent them nesting or risk losing the trees themselves. During the Tudor Period there were a series of poor harvests in the early 1500s. Henry VIII introduced a Vermin Act in 1532 “ordeyned to dystroye Choughes, Crowes and Rokes”, with the intention of protecting grain crops.
This act was largely unenforced and so in 1566 Elizabeth I passed the Act for the Preservation of Grayne, which proved more popular with large numbers of birds culled. The success of the legislation was perhaps due the bounties offered, with a bounty of one penny paid by parish wardens for three adult rook heads and a halfpenny for three young or eggs.
As well as shooting the birds, for centuries bird scarers were employed to scare away rooks, using all kinds of methods, from throwing stones to scattering rook feathers across a field without much success, as birds would continue to feed in areas they were being discouraged from. The ornithologist Francis Willoughby 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.
Perhaps the most famous deterrent was the ‘scarecrow’, which is perhaps wrongly named and should really be called the ‘scarerook’ as Carrion Crows seldom form large foraging groups unlike rooks. The Scarecrow was really designed to deter large groups of rooks and not a single or pair of Carrion Crows for the most part.
Even the modern-day deterrent of gas canons and reflectors, or even lasers do not dissuade rooks from feeding in fields for long, as they become accustomed and realize they will do no harm.
In New Zealand, despite their reputation as a pest, they were introduced by early ‘homesick’ white settlers from England who brought many of their familiar species into the country. However, as with many non-native species they became established in some areas and quickly became a pest and have subsequently been largely extirpated.
Despite their reputation as a pest and, the rather draconian measures to control them, they were often tolerated and some legislation often not put into practise. Indeed, not all interactions between man and rook are due to conflict. Gilbert White noted in the late 18th century that the poor in his area would collect sticks dropped from rookeries as brushwood for their fires and a rookery near their dwelling was considered fortuitous.
They were also considered good to eat and widely eaten, with rookeries allowed to flourish as they provided a good source of protein. Rook Pie was a staple at one time, with rich red meat tasting rather like rabbit. The young fledglings known as ‘branchers’ were considered the most delicious and up to a dozen rook breasts might be used in a pie. There was often a cull in May of the young birds, where the community would come together to shoot the rooks and eat them. They were at one point also widely poached, with the poachers climbing the trees of the rookery at night holding a lantern which blinded the adults and stop the rooks from calling out.
The rook was also seen as a weather indicator and their habit of soaring up high in large flocks known as ‘crow weddings’ were believed to show upcoming weather, with high aerial displays indicating fair weather and circling down low indicating rain.
Modern day research with captive rooks have shown them to be highly intelligent, almost on a par with Chimpanzees. Although they do not use tools in the wild, researchers have shown they quickly learn to use them to obtain food during experiments using captive birds. They are capable of problem-solving using these tools e.g., modifying and using a variety of tools, shaping hooks out of wire, and using a series of tools in a sequence to gain a reward.
They have even learnt to select stones of a certain weight and shape which they used to roll down a tube toward the base of a platform and knock some food onto the floor. They can also work singly or in groups and in another research experiment they learnt to collectively pull strings to open boxes and gain the food source inside.
All in all this rather drab and often overlooked bird is an avian marvel.
10. Fun Facts
- Rooks cache acorns just like the Jay.
- Rooks will tolerate Long-eared Owls nesting within a rookery.