Rook
| Irish Name: | Rúcach |
| Scientific name: | Corvus frugilegus |
| Bird Family: | Crows |
green
Conservation status
Conservation status
Status
Resident. One of Ireland's Top 20 most widespread garden birds.
Identification
A species of crow. All crows have sturdy legs and strong bills and are intelligent and social in nature. The Rook is a familiar bird, which nests in colonies in tree tops called rookeries. About the size of a Hooded Crow, the rook is all black and in certain lights can show a reddish or purple sheen to its plumage. Told apart from other species of crow by its 'trousers' the dropping feathers on its belly and the bare skin around its bill base on the adult birds. Juveniles lack this feature, which only develops in the spring of its second year, and then they can be difficult to separate from Carrion Crows (a rare breeder in Ireland); best told apart by the more peaked crown of the Rook. Often forages in the company of other crow species, especially Jackdaws. When separating Hooded Crows and Rooks in flight, Rooks has faster and deeper wingbeats, which makes it look like they are making more effort than the Hooded Crow.
Voice
A hoarse croaking call. When given in the colony can be very loud.
Diet
Feeds mainly on invertebrates. Food also includes small vertebrates, carrion, plant material and scrapes of all kinds. Found feeding in agricultural areas on pastures, fallows, occasionally in trees. Also found in town and cities feeding on refuse and food scraps.
Breeding
Builds a untidy nest in the tops of trees, usually quite high up, but not always can be quite close to the ground if the trees are short. In the late winter rookeries are a hive of activity as birds get ready for the coming breeding season. The species is widespread and abundant in Ireland breeding in all areas, it is only absent from the centre of towns and uplands areas. Rare or absent in parts of the west coast.
Wintering
Widespread in the winter when it forms large flocks, often with Jackdaws.
Monitored by
Almost ubiquitous resident, absent only from expansive uplands. Breeds colonially in Rookeries.
Gregarious, often in flocks numbering in the hundreds. Forms large winter roosts sometimes neighbouring with Jackdaw.
Blog posts about this bird
Must Be the Season of the Corvid
Maybe it’s the Raven’s ominous ‘Nevermore’, the attacking crows in Alfred Hitchcock’s The Birds, or the fact that a flock of crows is called a ‘murder' — no group of birds quite encapsulate Halloween like Corvids. Although Corvids don’t deserve the bad rap they are given, their curious behavior and haunting caws don’t help their case in the court of public opinion. Instead of feeling haunted by your neighborhood Magpie this spooky season, learn more about some of our common Irish Corvids and how to tell them apart.
As our largest songbird, Ravens are slightly larger than Buzzards. Adults show an all-black, glossy plumage with shaggy throat feathers. They have thick, black beaks that help their varied diet. Like other members of the crow family, Ravens are incredibly intelligent and have been known to engage in playful behaviour, such as flipping upside down with closed wings. They are social birds, and young Ravens can be found roosting together in large groups during the winter. In flight, they can be identified by their wedge-shaped tail. Bonus fact, Ravens often only have one mate for life!
Hooded Crows may be one of the easiest crows to identify, thanks to their unmistakable grey body and black head, throat, wings, and tail. These crows are also incredibly intelligent and have been recorded using crafty methods to crack open nuts, such as placing the nut on the road and waiting for a car to break the shell.
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And, of course, no Irish Corvid list would be complete without the Magpie. Unlike the other species listed above, Magpies have a splash of colour in their plumage. Their head, chest, back, and tail are black while their belly and flanks are white. In the right light, you can discern a green and blue gloss on their wings and tail. Juvenile birds are very similar to adults but lack the long tail, which takes a while to grow!
Raven
As our largest songbird, Ravens are slightly larger than Buzzards. Adults show an all-black, glossy plumage with shaggy throat feathers. They have thick, black beaks that help their varied diet. Like other members of the crow family, Ravens are incredibly intelligent and have been known to engage in playful behaviour, such as flipping upside down with closed wings. They are social birds, and young Ravens can be found roosting together in large groups during the winter. In flight, they can be identified by their wedge-shaped tail. Bonus fact, Ravens often only have one mate for life!
Raven
Rook
Besides being smaller than a Raven, a distinctive clue to identifying adult Rooks is the bare, pale base of the bill and shaggy feathers on the thighs that makes them appear to have trousers. Rooks are one of Ireland’s most common birds and can be seen across the island, nesting in noisy colonies called rookeries. When separating Hooded Crows and Rooks in flight, Rooks have faster and deeper wingbeats, which makes it look as if they are making more effort than the Hooded Crow.Hooded Crow
Hooded Crows may be one of the easiest crows to identify, thanks to their unmistakable grey body and black head, throat, wings, and tail. These crows are also incredibly intelligent and have been recorded using crafty methods to crack open nuts, such as placing the nut on the road and waiting for a car to break the shell.
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Hooded Crow
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Jackdaw
Smaller than the other species here, the Jackdaw has a short black bill and a pale, silvery eye. Like the Hooded Crow, Jackdaws have a black and grey contrast between the head and throat, but it is much less drastic. They are widespread across Ireland, but are less common in the mountainous areas of the west. During roosting season, Jackdaws can be found in the company of other crows, especially Rooks. They practically say their own name with the sharp 'chack' of their call.Magpie
And, of course, no Irish Corvid list would be complete without the Magpie. Unlike the other species listed above, Magpies have a splash of colour in their plumage. Their head, chest, back, and tail are black while their belly and flanks are white. In the right light, you can discern a green and blue gloss on their wings and tail. Juvenile birds are very similar to adults but lack the long tail, which takes a while to grow! 
Magpie
Do Rooks nest in your CBS square? Dr. Fionn Ó Marcaigh
Colony counts and Rookeries: Do rooks nest in your CBS square? If so, we’d like you to take a closer look…
Dr. Fionn Ó Marcaigh, CBS Project Officer in the NPWS Scientific Advice and Research Directorate
CBS transect surveys are one part of this, so if you see any rooks on your transects, record them like any other species. You can identify a rook by its uniformly dark plumage, the patch of grey skin at the base of its bill, and the feathers around its legs that resemble a pair of baggy trousers. Although they are rather plain-looking birds overall, when seen up close or at certain angles their plumage can take on a rather pretty purplish gloss. They are vocal but not particularly musical, with a voice similar to a hooded crow’s but even more croaky and dry. The way the Collins Bird Guide puts it is that hooded crows roll their Rs and rooks don’t! While doing your transects and exploring your square, watch out for any rookeries nearby. We are particularly interested in data on rookeries as it can tell us how the breeding population is faring. At the end of your CBS Count Summary Sheet, you will find a section for Colony Counts, where you can record nest numbers in any rookeries you find. Rookeries are often found near villages and small towns, and they can be so busy and noisy, particularly in the evening, that you may hear a rookery before you see it!
Curry Rookery by Fionn Ó Marcaigh
When you’ve found a rookery, make a count or estimate of the number of apparently occupied nests. You might find it helpful to use binoculars and look at the colony from multiple positions. You don’t need to spend too much time ascertaining whether a given nest is occupied or not, however: the overall number is what’s important. You might not be able to stop and count nests when you’re doing your main CBS transect counts, so your colony counts can be done separately from the transects and don’t have to be on the same date. You aren’t restricted to your transect routes, either: you can count colonies anywhere within your 1 km x 1 km square. CBS visits take place in the period when rooks are busy nesting, but the emerging leaves will make counting nests difficult, especially on your late visit. So if you do have a rookery in your square, consider visiting it specially and making a count before the leaves have hidden the nests. The first couple of weeks in April are often suitable. We’re grateful for the colony counting that CBS surveyors have already undertaken. In the 2024 CBS, the largest rookeries counted were in Counties Laois and Wexford, each with 220 nests. Now we’re hoping to get more and more counts, and we’d also be glad if people who have counted rookeries previously would return and count them again each year, to show any changes over time. In a way, a rookery is like a town in itself, being built up by a community of birds over years. Rooks are industrious, clever builders, and in old Irish rookeries some nests have been measured at nearly 2 metres wide. Our countryside provides ample food for these little societies. A 1984 National University of Ireland PhD thesis by Ron Macdonald found 66 rookeries in a 100 km2 area of Co. Kildare, containing nearly 5,000 nests. With typical corvid resourcefulness, rooks are adept at providing for themselves, and this sometimes involves a bit of pilfering of the local produce. In their 1900 book The Birds of Ireland, Ussher and Warren describe mobs of rooks walking along drills of turnips during crop thinning, pulling the plants up one by one, until they had gone through entire acres of them. In fact, the scarecrows that are put up to protect crops are largely aimed at rooks, more so than other corvids. Being so adaptable, however, I have also seen rooks foraging in quite different habitats, for example picking through small shellfish on the shore.
Curry Rookery by Fionn Ó Marcaigh
Conflict over crops has caused trouble for the species: as abundant as they are in Ireland, you might be surprised to learn that rooks are on the decline across Europe. In the latest European Red List of Birds published by BirdLife International in 2021, the Rook was put in the Vulnerable category, a serious change from its listing as of Least Concern in the 2015 edition, which the authors attributed to persecution. Even here in Ireland, CBS results indicate a moderate decrease in their population since 1998. This is why we are so keen to collect data on our rookeries. These birds are a quintessential part of the Irish landscape, and the data that we all provide through the CBS is an important part of understanding and protecting them.
