Harrier Bird

Harrier is any species of hawks that belongs to the subfamily of Circinae. This subfamily comes under the family Accipitridae, which is a family consisting of several birds of prey. The Harrier bird or the Harrier hawks are mostly found active during the day time and are inactive during the night thus making them a diurnal species of organisms. They are characterized by their low flight on open grounds for hunting small mammals, reptiles or birds. The young harrier bird is typically known as a ring-tail harrier. Their main noticeable characteristics include long wings, a long narrow tail, the slow and low flight over grasslands and skull peculiarities. 

The Naming of the Harrier

The name Harrier is thought to have originated from Harrier dog, which is a medium sized dog belonging to the Hound family. It can also have come from a corruption of the word harrower or from the word harry. Thus, harrier meaning is not specific and has become more part of a cultural aspect which was later included in the scientific literature as well for classification. The genus Circus, however, was identified for the first time by French naturalist Bernard Germain de Lacépède in the year 1799. The species that was used for characterization of the genus was the western marsh harrier. An image of the western marsh harrier is given below:

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Unlike the Harrier, ring-tail is an informal term used for the young Harriers. It is commonly used by bird watchers or birders for both juveniles and females of many different species of Harrier when seen in the field and unable to be identified to an exact species. The most commonly observed ring-tails belong to the species of Montagu’s harrier (Circus pygargus), Hen harrier (Circus cyaneus), and Pallid harrier (Circus macrourus). 

Understanding briefly about some of the species of harriers, will help you understand more about the subfamily of birds of prey and also to know more about some of the common species of harriers. Moving down in the article you will find a brief description of different species types of Harriers. 

Western Marsh Harrier

The scientific name of Western Marsh harrier is Circus aeruginosus. It is the type species for the genus Circus. It is a large bird of prey belonging to the temperate and subtropical climate of western Eurasia and the adjacent Africa. Therefore, it is also known as Eurasian Marsh harrier. The birds in this species are further classified into two subspecies. The Circus aeruginosus aeruginosus are widely migratory birds and are found all over the region of their common occurrence. The other subspecies is Circus aeruginosus harterti which is a resident of Africa and can be found there only any time of the year i.e. they are not migratory in nature. An image of the western marsh harrier is given below: 

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These are usually 44 cm - 50 cm in length with a wingspan of typically 115 cm - 130 cm. A healthy adult male will weigh anywhere between 400 gm - 650 gm and a healthy adult female of the species can weigh anywhere between 500 gm - 800 gm. It is one of the large and bulky harrier species - larger than most european harriers but smaller than the Eastern Marsh Harrier. They have fairly broad wings and have a strong and peculiar sexual dichromatism. The layering of the feathers or the plumage of a male western marsh harrier is usually reddish brown in colour with light yellowish streaks and are prominently found on their breast, all of which makes them adjust and mix in the open land environment where they are commonly found helping them in being hard to be identified. The head and the shoulders are mostly of pale yellowish or greyish colours. The feathers of the tails and the secondary and tertiary feathers on the wings are pure grey. These are in contrast to the brown forewing and the primary feathers on the wings which are black in colour especially at the wing tips. This colour pattern is the same on the upper side and the down side of the wing although the colour on the down wing can be lighter. 

On the other hand, the females of this species are entirely almost chocolate brown in colour. The top of the head, the shoulders and the throat usually have a quite visible light yellowish colour. It can be clearly delimited and very contrasting or be particularly more washed out giving resemblance to the male head. The eye area of the females is always darker due to which the eye stands out. The females lack a grey wing-patch on the tails. The juveniles or the young ones of these species are similar to the females but have a little less yellowish patch on the shoulders. 

Due to several human activities there has been a considerable increase in the habitat losses for the birds of this species. This led to a decrease in the population of western marsh harriers during the 19th and the 20th centuries. This decrease has also been observed due to the excessive use of pesticides. Hence, it has been included in the protected status in many countries. It has been classified as species of least concern by the IUCN. 

Eastern Marsh Harrier

The eastern marsh harrier is scientifically known as Circus spilonotus. It is a bird of prey collectively included in the marsh harrier group of harrier hawks. Previously it was included with the western marsh harrier but is now classified as a separate species. The birds in this group are further classified into two subspecies as well. They are: Circus spilonotus spilonotus more commonly found in eastern Asia and Circus spilonotus spilothorax more common in New Guinea. An image of an Eastern marsh harrier is given below:

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The birds in this species are 48 cm to 50 cm long and have a total wingspan ranging between 113 cm to 137 cm. Even in these species and like most birds of prey, the females are larger than the males. The colour of the feathers of the male is quite variable. The feathers present in the head, breast, back and wing-coverts region are blackish with pale streaks. The rest of the wing is of grey colour and has black wing-tips with a white front edge. The tail is of grey colour and the rump is of white colour just like the underside of the wings. The female of this species is usually of dark brown colour with buff streaking on the head and the underparts. The rump is of white colour like the male and the tail has dark bars. The young ones also have a buff on the head like the females and are of dark brown colour and have a pale patch on the underwings. 

These are generally migratory birds except the Papuan harrier. The breeding range covers north-east China, Mongolia, and south-east Siberia with small numbers in northern Japan. Their wintering range includes the regions of southern China, Taiwan, Korea, southern Japan, northeast India, Bangladesh and south-east Asia as far as Philippines, Borneo and Sumatra. The most preferable habitat for the eastern marsh harrier is the open country which includes marshland, paddy fields and grassland. 

Northern Harrier

The scientific name of the northern harrier bird of prey is Circus hudsonius. Mostly the bird is found in the northern hemisphere and is hence named as northern harrier. You can find a northern harrier in the regions of Canada and northernmost USA. It is also sometimes referred to as hen harrier by some taxonomic authorities but many consider both of them to be distinct species. It is a migratory bird and travels to more southern areas during the winter season. These areas include the region of southernmost USA, Mexico and Central America. Sometimes because of the comfortable atmosphere in the milder regions in the southern USA, they can be found in these regions during the entire year. Typically, these birds are found in prairies, open areas and marshes. An image of a northern harrier is given below:

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The northern harrier hawk is about 41 cm to 52 cm long. They have a wingspan of 97 cm to 122 cm. The colour of the feathers or the plumage of these harriers is quite in resemblance to other harriers. The male of this species weigh from 290 gm to 400 gm with an average weight being around 350 gm. The females weigh from 390 gm to 750 gm and the average weight is around 530 gm. These hawks have relatively long wings and long tails, especially being the largest winged and tailed as compared to the body size of any raptor in the entire region of North America. 

Although some taxonomists classify the northern harriers along with the hen harriers, it is now clear that the hen harriers and northern harriers are different species based on the genetic analysis. Species-wise these birds are the closest relative to the Cinereous Harrier (C. cinereus). The plumage of the male is darker grey as compared to the plumage of hen harrier male. The same is true for the females as well. Due to the striking plumage and the spectral aura, sometimes, the adult male northern harrier is also commonly known as “Grey Ghost”. The female normally gives a whistled pooh-eh when it receives the food from the male and the alarm call is chit-it-it-it-it-et-it. Similarly, the male calls is chek-chek-chek, with a bouncing chuk-uk-uk-uk sound during the display flight. 

These northern harriers have also played a significant role over time in becoming amalgamated with human culture. For example, some of the native American tribes believe that seeing a northern harrier hawk on the day of wedding is a sign of a long and a happy marriage. Also, unlike many other raptors, hen or northern harriers have been traditionally favoured by the farmers as they eat mice and predators that can lead to damage of the crops. That is why harriers are sometimes known as “Good hawks”. This is also because they are no threats even for poultry farming like the other hawks. But because of heavy pesticide use during the 1970’s and 1980’s has led to the decline in the population of harriers. Even though, the species has a very large range, a population decline has been observed for the population. Although there is a decline it is not near the threshold required by the IUCN to classify it in the Red list and hence it is classified as a species of “least concern”.

Montagu’s Harrier

The Montagu harrier, having the scientific name Circus pygargus, is also a migratory bird of the harrier subfamily. The naming of the bird is in respect of the British naturalist George Montagu. An image is given below:

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The adult males in this species have an overall pale grey plumage except the wingtips where it is black in colour. In comparison with the other hawks of the harrier family, these species have black bands on the secondary layer feathers of the spotted wings which characterize the species. These dark bands are observed both above and below the wing and the rusty streaks are found on the belly and the flanks. The adult females have a broad and similar plumage to pallid and hen harriers. A pale yellow-brown colour is observed in the underparts along with longitudinal stripes in the belly and the wings. On the other hand, the upper parts are uniform and have dark brown colour except for white upper tail coverts, known as rump, and a slightly paler central wing having coverts. 

The colour of the feathers of the young harriers is similar to that of the female with the only difference being in the belly and underwing region which are not spotted instead have a uniform red-brown colour. One can also observe melanistic forms occurring regularly in these species. In the melanistic forms, the male is darker than the usual and has a black head, brownish-black above with grey underparts. The melanistic females have entirely chocolate brown colours on their body except for their feathers which were of grey colour. Some partial melanistic forms are also found. 

The Montagu’s harriers are known for their particularly graceful flight and have powerful and elegant wingbeats which provide an impression of buoyancy and ease. As it is a general characteristic of the harrier, the Montagu harriers search the countryside, flying low and keeping and holding their wings with a marked positive dihedral. It is a deceptively small raptor even though with the entire wing surface it can appear large compared to the small body weight. This gives a typical buoyant flight to the birds. In these species as well the female is larger than the males. 

The Montagu harrier species can be found throughout most of the Western Palearctic. Small populations are also found in most of the European nations except Norway, where it is completely absent. The area also covers the far regions of Urals, and in the west till Portugal. The breeding also occurs in the regions of northern Africa, especially in Morocco. In Great Britain, the hawk is found in southern England and rarely seen in Ireland almost exclusively to the South. Although found widely across the world, the strongest populations of these hawks are found only in France, Spain, Belarus, Russia and Poland, containing the maximum of the European population. But due to increase in population decline the distribution of these hawks has become limited to their strong population zones only. 

It is observed and estimated that almost 70% of the population of these breeding pairs of these harriers nest in the agricultural farmlands of western Europe. They can especially be found in the fields of cereal crops. Hence, this characteristic of the Montagu makes them quite vulnerable and their survival depends on the protection capabilities of the nest. They are helped in this effort by several Bird protection NGOs which participate in activities of their protection along with the landowners. They simply relocate a nest to a safer area or to a protected space where they will not be harvested. Because of these kinds of steps, an average of 60% of the young ones are saved in the nest. 

Hen Harrier

Circus cyaneus is more commonly known as the Hen Harrier. The latin name cyaneus means dark blue. An image of the hen harrier is given below:

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The Hen harrier is commonly found in Eurasia. The name “hen harrier” comes from the bird’s habit of preying on the fowl. During the winter these birds migrate to the southerly areas. Eurasian birds then move to southern Europe and southern temperate Asia. In mild regions such as France and Great Britain, the harriers may be found all year long but will leave any higher ground during the winter. Also, they have been found to be genetically different from the northern harrier. They have a very similar build like the northern harrier

The Hen harrier has become a part of human culture in Europe. In some parts, it is believed that seeing a harrier perching on the house was a sign that three people would die. Also, like the other harriers these harriers are also considered good for agricultural activities and by the farmers. But recently there has been a decline in the population of hen harriers. It has been declining more than 30% in a period of ten years or an estimated three generations. It is classified as a species of least concern by the IUCN. But in the United Kingdom, the harrier populations have gone into critical condition because of habitat loss and illegal killing on the grouse moors. In 2012, only 617 pairs were present which was a 20% fall from 2004.