Hen Harriers are one of the birds that is distinctive of upland habitats but, sadly, it is also one of our most threatened. They have suffered for many years, persecuted for the belief they took farmyard fowl, and driven from suitable habitats by forestry and the planting of huge areas of trees. They also prey on Red Grouse chicks, one of the naturally occurring birds in the upland heather moorlands where Hen Harriers breed, along with Meadow Pipit and waders. Unfortunately Red Grouse are both economically valuable due to the revenue they bring through game shooting and also bred in huge numbers meaning they are far more common on those moorlands than they would naturally be – just too much of a temptation for the harriers, who are seen as a threat to the industry and subsequently suffer persecution.
Key facts
Common name: Hen Harrier
Scientific name: Circus cyaneus
Habitat: Upland heather moors, mostly in Scotland, in winter they are found more widely across the country and may be found anywhere there are open habitats, although they favour rough grasslands and heaths.
Diet: Small birds and mammals but will take insects, reptiles and amphibians when available
Size: Average 48cm, wingspan 110cm. Females (500g) larger than males (350g)
Status: Resident breeding bird. Migrant. Passage and winter visitor
Population size: 545 pairs
Conservation status: RED (due to long-term population and range decline)
Appearance
Male Hen Harriers are distinctive birds, plain silver grey above, with long narrow wings and black tips and a dark trailing edge. They have a white rump and a long grey tail. They are mostly white below and typically hold their long wings in a ‘V’-shape. The females and juveniles are less obvious – being brown and heavily streaked, but they share the white rump (and are often referred to as ‘Ringtails’). All Hen Harriers show five ‘fingers’ at the wing tip, and this separates them from the rarer harriers that may also occur. All harriers have owl-like facial masks, and this bears testament to the fact that a lot of their hunting is done through sound.
Lifespan
The average lifespan is 7 years, with an adult survival rate of 81% year on year. First year survival is not known, but birds have a 22% chance of reaching their second year, when they will begin breeding. The oldest known wild bird in the world was 15 years and 9 months old (ringing recovery).
Nesting
Hen Harriers nest on the ground, either deep in the low vegetation or on a slight incline. The nest is relatively simple, just a scrape with some sticks, grass, and leaves. Hen Harriers practice polygyny – where one male will mate with and provision the nests of more than one female. Research has shown that this is more likely when food availability is high.
Number of eggs: 4-5
Incubation: 34 days
Fledging time: 37-42 days
Habitat and Distribution
During the breeding season Hen Harriers are very much birds of upland heather moors, mostly in Scotland. Elsewhere in their large world range, across Europe and Asia they have a wider habitat tolerance when breeding, and can be found in grassland, agricultural crops and even marshes. A tiny population occurs in northern England, with others in North Wales and in Ireland. In certain areas, they are more commonly encountered, such as on Orkney and Isle of Man. In winter they are found more widely across the country and can, potentially, be found anywhere there are open habitats, although they favour rough grasslands and heaths.
Movements
Hen Harriers range widely in their first couple of years before settling to breed and may travel far from their natal sites. In winter British birds may move to lower altitudes and may head south into England or even further afield, although ringing has shown that many of the birds that occur in southern England in winter have originated from northern and central Europe. Other populations of Hen Harriers are strongly migratory.
Feeding
Hen Harriers, as with all the harrier species, hunt low over the ground, slowly quartering an area looking and listening for prey. They principally take small birds and small mammals, but they are adaptable and will take insects, reptiles and amphibians when available. They often target nestlings, and will tackle larger prey, which they have been observed drowning to subdue. Hen Harriers have also been seen hunting bats. Nestlings of passerines and waders are targeted, but the high density of gamebirds in the habitats that Hen Harriers breed in means that grouse chicks are targeted, usually when the harriers have extra demands due to feeding their young.
Marsh Harriers have always been part of the avifauna of the UK, but numbers dropped dramatically as the fens and wetlands in the east were drained for agriculture. The population took a further hit in Victorian times, as birds were targeted as predators by hunters, farmers and landowners at the same time eggs were being collected or destroyed, and habitat continues to be lost. By the late 1800s they had become extinct in England and the last pair bred in Ireland in 1917. Occasional birds, almost certainly originally from the continent, bred in Suffolk and Norfolk, with the core being at Minsmere reserve, but numbers increased in fits and starts up to the 1950s. A resurgence was expected but numbers crashed again, and by 1961 no Marsh Harriers bred in the UK. This time it is believed that the population crash was caused by the use of organochlorine pesticides, especially in their Scandinavian heartland. They did maintain a toehold, with one nest annually at Minsmere until the use of pesticides was banned. Numbers began to climb once again and now, thankfully, these magnificent birds are an integral part of the fens, marshes and reedbeds of Eastern England.
Key Facts
Common name: Marsh Harrier
Scientific name: Circus aeruginosus
Habitat: Reedbeds and other well vegetated habitats
Diet: Small mammals, birds, insects, reptiles, frogs and even, on occasion, fish
Size: Average 52cm, wingspan 122cm. Females (670g) larger than males (540g)
Status: Resident breeding bird. Migrant and passage visitor
Population size: 590 pairs
Conservation status: AMBER (recovered from historical decline, but recent population and range declines)
Appearance
They are sexually dimorphic in plumage, with adult females a handsome chocolate brown colour with cream heads and forewings, whereas the males have a complex pattern of brown, russet and grey. Juveniles tend to have a female-like plumage. Study of a number of birds of known age, however, has shown that plumage in Marsh Harriers is not straightforward, with some older birds having juvenile-type plumage, and some old females developing male-type plumage! They are quite large birds, heavier and sturdier than our other harriers, and have long wings often held in an upward ‘V’ shape, reminiscent of Buzzard or Black Kite which can cause a confusion, especially when encountered away from their usual wetland habitats. However, the low, inconspicuous quartering back and forth over the hunting site is characteristic. Marsh Harriers are not closely related to the other harrier species found in Britain but form a group of species which occur across Asia, Indian Ocean islands and Australia.
Lifespan
The average lifespan is 6 years, with an adult survival rate of 74% year on year. First year survival is not known, but birds have a 15% chance of reaching their third year, when they will begin breeding. The oldest known wild bird in the world, was 6½ years old (ringing recovery).
Nesting
Invariably, Marsh Harriers nest on the ground in long vegetation. British Marsh Harriers have always nested in reed beds, although in Europe they nest in rank vegetation and even in agricultural crops. Since recolonising, some British harriers are starting to show a wider breeding habitat, with records of crop-breeding and even moorland-breeding. This change of behaviour should offer opportunities for the recovering population. It is common for males to support more than one female. On occasion one male may be paired with three females, although breeding success is often lower as the male is not able to provision all the nests and chicks sufficiently.
Number of eggs: 4-5
Incubation: 31-38 days
Fledging time: 35-40 days
Habitat and Distribution
Marsh Harriers are still very much birds of eastern England, centred on East Anglia and the eastern coast. Small populations also occur in a number of places, most notably Lancashire and Dorset. In winter, as birds range more widely, they may be encountered anywhere but are still very rare outside of their core areas. During the breeding season, Marsh Harriers are typically seen in extensive reed beds, but a few can be found in other open, well-vegetated habitats. After breeding, birds range more widely, and can be found in coastal areas and even quartering fields; in East Anglia, some seem to favour stubble fields in the autumn
Movements
It is almost certain that the recolonising birds originated from Europe, and for many years Marsh Harriers were regarded as migrants, but in fact birds are more likely to remain all year. As birds are three before breeding, they spend their first two years ranging widely away from where they were hatched, and this may include leaving the country, through southern Europe and even as far as Africa (several wing-tagged birds have been recorded south of the Sahara). It is likely that some adult individuals will leave the country, whilst others show remarkable loyalty to their territorial areas. Birds may appear at winter harrier roosts with Hen Harriers.
Feeding
Marsh Harriers are catholic in their diet but prefer to take their prey from the ground. They will target small mammals, birds, insects, reptiles, frogs and even, on occasion, fish. As with other harrier species, they can exchange food with their mates in mid-air.
Goshawk are well-known as feisty and difficult falconers’ birds, and their scientific name gentilis derives from the fact that traditionally only members of the gentry or nobility were allowed to carry one. Goshawks are the largest of the accipiter/hawk group of birds of prey and are found across much of the northern Hemisphere. In much of their range they are one of the top predators, but share their habitat with other, smaller, accipiters such as Sparrowhawk in the UK and Sharp-shinned and Cooper’s Hawks in North America.
Key Facts
Common name: Goshawk
Scientific name: Accipiter gentilis
Habitat: Woodland
Diet: Birds such as Woodpigeon and Corvids. Squirrels and other small mammals
Size: Average 55cm, wingspan 110cm. Females (1.5kg) larger than males (850g)
Status: Reintroduced resident breeder
Population size: 620 pairs
Conservation status: GREEN (Least concern)
Identification of Goshawk can be difficult, especially with fleeting views or where size is not apparent. Adults should be reasonably obvious, with grey/brown backs, dark caps and cheeks and pale eyestripes with very fine barring on the pale undersides. Young birds are brown above and have dark ‘drop’ marks on the chest, as opposed to young Sparrowhawks which are coarsely barred below, but young female Sparrowhawks are often identified as Goshawk. A large female Sparrowhawk can approach the size, if not the bulk, of a male Goshawk, but female Goshawks are Buzzard-sized.
The average age in the wild is 7 years. Adults have an 83% year-to-year survival rate. First year survival is not known, but birds have a 40% chance of reaching their second year. The oldest known wild bird was almost 19 years old (ringing recovery).
Goshawks build large stick nests high up in a tree, usually a conifer. They are highly secretive whilst nesting, but when displaying on fine days in early spring, high above the trees, they can give their presence away and this is often the best time to see this elusive species.
Number of eggs: 3-4
Incubation: 35-38 days
Fledging time: 35-42 days
Goshawk share the same short blunt wings as their smaller cousin, Sparrowhawk, which gives a clue to their woodland habitat. Enabling them to move rapidly and agilely through dense vegetation, Goshawk are supremely adapted to life in wooded areas. The majority of birds are found in woodland, and they are prone to disturbance, so tend to be found in remoter areas; they are extremely rare in urban areas and are highly unlikely to be found taking birds in gardens. They are most likely to be encountered in Wales and southern and eastern Scotland, but there are also well-known populations around Dartmoor, New Forest, Thetford Forest, Pennines and Northumberland. It is believed that the population is increasing, but numbers are still too low for it to be monitored by standard bird surveys.
Throughout their huge world range, Goshawks can be highly migratory, but British Goshawks are invariably sedentary. Occasionally young birds and migrants wander to the UK from northern Europe where they may be more migratory in response to varying food availability. It is possible that some of the recent populations come from continental birds.
Goshawks are formidable hunters and often seem fearless, with many accounts of them tackling much larger prey than themselves. They are certainly adaptable but will also actively target perceived threats and competition such as Buzzard, falcons and owls; in fact, in Europe Goshawk is the second most frequent cause of predation on owls after Eagle Owl. In the UK most prey taken are birds, with Wood Pigeons and members of the Crow Family being favourites. In some areas, such as North America, mammals may also feature highly and a study in Thetford Forest showed that over 50% of the food fed to chicks in the nest was Grey Squirrel. Food availability is unlikely to be a factor in suppressing numbers of Goshawk which are presently well below expected carrying capacity in the UK. They are adaptable and catholic hunters, making use of any opportunities. They invariably hunt by sitting and watching, combined with short, stealthy flights between perches. Once prey is spotted, it can be caught in a number of different ways, but Goshawk are even known to hunt by foot on the ground in very dense habitats. Most prey are likely to be taken by surprise, although long, agile chases occasionally occur, especially if the hawk is hungry.
Sparrowhawks are short-winged birds of prey, perfectly designed for rapid maneuvering amongst the heavily vegetated areas in woodlands which are their main habitat. Many birds of prey exhibit sexual dimorphism – differing sizes of male and female – the largest difference of all is Sparrowhawk, where females can be 25% larger than the males. It is believed that this ensures both birds can hunt different prey, and not come into conflict over limited prey, especially in winter. Particularly in the early stages of pairing up in the spring, males must be cautious, as they are well within the range of female prey and it is not unknown for males to be taken, although they are more agile than the heavier females.
Key Facts
Common name: Sparrowhawk
Scientific name: Accipiter nisus
Habitat: Woodland, gardens, farmland, urban areas
Diet: Small birds
Size: Average 33cm (male) 37cm (female); wingspan 62cm (male), 74cm (female). Females (260g) much heavier than males (150g)
Status: Resident breeder and passage/winter visitor.
Population size: 31,000 pairs
Conservation status: AMBER Listed
Appearance
Males are blue-grey above with fine orange barring beneath, females are grey-brown and white. Young birds are browner with coarsely barred chests. The only likely confusion species is Goshawk. Females can be 25% larger than the males.
The colouration, size and even flying style of Sparrowhawks is very similar to that of Cuckoo, and it is believed that Cuckoos have evolved this, as other small birds see them as predators, rising off the nest to ‘mob’ a potential predator and, in the process, revealing the location of their nests which the female Cuckoo will be looking for to lay her eggs in.
Lifespan
Typical lifespan of 4 years, with an adult year-to-year survival rate of 69%. First year survival is just 34%. The oldest known wild bird was just over 17 years old (ringing recovery).
Nesting
Sparrowhawks nest in messy stick nests in trees, often deep in forested areas, although they will nest in parks, large gardens and small wooded patches. They are quite shy whilst breeding, but when they have well-grown chicks in the nest, their incessant begging can give the location away.
Number of eggs: 4-5
Incubation: 33 days
Fledging time: 27-31 days
Sparrowhawks are single-brooded and will breed in the year after hatching.
Habitat and Distribution
One of our most frequent and familiar birds of prey, Sparrowhawks are birds of woodland, but they have adapted to life in our mosaic habitats, including gardens, farmland and even urban areas. Sparrowhawks occur throughout the whole of the UK, although they are scarcer in the north and west. Numbers crashed in the latter part of the 20th Century, due to pesticides used as seed dressings accumulating in their bodies through eating contaminated prey. This poisoning caused thinned eggshells leading to breakage in the nest. From the 1970s, after these chemicals were banned, the population slowly recovered, leading to stability in the 1990s. Numbers have dropped slightly in the last decade.
Movements
Most British Sparrowhawks remain rather sedentary, although young birds can move significant distances in the search for a territory. Birds from northern Europe migrate here for the winter and can often be encountered in the east.
Feeding
Reliant on small birds, which are often caught in a twisting, agile flight. Despite their name Sparrows are not particularly sought, but any small bird is a potential target. In gardens tits are frequent prey, and males will frequently hunt birds up to the size of a Blackbird. Females tend to target larger prey and commonly tackle Collared Doves and Wood Pigeons. Prey is usually dispatched with their very long toes and talons, but distressingly plucking can often begin before the prey is dead. Larger prey, such as Magpies, is often drowned.
Although well-known as a visitor to garden bird feeding stations, only 10% of Sparrowhawk hunting flights are successful. They use a variety of hunting techniques, but perhaps the most characteristic one is to fly low on the far side of a hedge or fence, before flipping over the top and surprising the birds on the other side. Some small birds, such as Blue Tit have a specific warning call they give if they spot a Sparrowhawk. Other birds, including other species, can understand this call and also seek cover. The call will also alert us to the near-by presence of a Sparrowhawk!
Our Mission
We believe in a world where birds of prey and their habitats are safe, thriving, and accessible for all to experience and protect.
Through dedicated conservation efforts, research, and education, we work tirelessly to preserve these magnificent species and the environments that support them.
How You Can Help
Your support makes our conservation efforts possible. There are many ways to get involved:
Become a Member, Volunteer or Donate
Join our community and gain exclusive access to member events, updates, and more. Every donation directly supports our projects and conservation efforts.
Experience the Wild
Visit our nature reserves and witness raptors in their natural habitats. Our reserves are open to the public, offering a unique opportunity to see conservation in action and connect with nature.
Plan Your Visit
From walking trails to guided tours, our reserves offer a memorable experience for all ages.
