The genus Circus is a cosmopolitan genus of about ten species. They are medium-sized, slender hawks, the female being considerably larger than the male. They are characterised by long, narrow, rounded tails, small beaks and long, slender legs. The most notable characteristic is the owl-like ruff of facial feathers that cover unusually large ear openings – an adaptation not for low-light hunting, but to locate prey by their rustling and squeaking in tall grasses.
Adult females have a broadly similar plumage to that of Pallid and Hen Harriers. The underparts are mostly pale yellow-brown, the belly with longitudinal stripes and the wing coverts spotted. The upper parts are uniform dark brown except for the white upper tail coverts (“rump”), and the sightly paler central wing coverts.
The juvenile plumage resembles that of the female, but differs by the belly and under wing coverts which are not spotted, but uniformly red brown in colour.
A melanistic form occurs regularly in this species. In this form the male is much darker than usual, with a black head, brownish black above and grey underparts. The melanistic female is entirely chocolate brown except for grey flight feathers. Partially melanistic morphs can also be found.
Listen to the sound of Montagus Harrier
Copyright remark: Most sounds derived from xeno-canto
It is essentially a lowland species, and breeds readily in dry areas, such as heath land, sand dunes and young plantations. It does not tolerate disturbance, and avoids areas that are subject to any form of human habitation and use.
When no other suitable habitat is available this harrier will nest in agricultural farmlands where it is vulnerable to early harvesting. Amongst these it chooses especially grasslands and cereal crops such as wheat, barley, oats and colza. In western Europe, up to 70 percent of the population breeds in artificial habitats.
The courtship ritual involves the pair circling together to a great height, and playing a number of mid-air games including food-passes, diving, rolling and talon presentation.
The nest is constructed on the ground, in natural or cultivated vegetation, moorland, young forestry plantations or even sand-dunes. Building, mostly by the hen, takes about 4 days. The hen also takes the brunt (if not all) of the incubation duty, which lasts for about 30 days per egg – up to around 40 days for the full clutch of up to four or five eggs.
The young remain in the nest for about 3 weeks, when they start to crouch in surrounding vegetation, although still very much under the protection of the adults until they fledge at bout 42 days. Full independence is achieved about 14 days after fledging.
Video Montagus Harrier
The Montagu’s Harrier is possibly the most slender and elegant of its genus. Its body and wing form can, at times, cause it to be mistaken for a falcon. In flight it is the most buoyant of the Harriers and is reminiscent of the flight pattern of a tern – the slow glides interspersed with half a dozen wingbeats of such power that the bird lifts visibly.
Its hunting method is typical of its genus, quartering the land at low speed and low altitude, but with the ability to drop quickly and silently onto its prey once located.
Being a ground-nesting and roosting bird, this species, as well as suffering the persecution and indiscriminate shooting that has been the lot of many raptors over the last century or so, falls prey to the ravages of farm machinery (except where the farmer is aware of their presence and sufficiently interested to take some positive action). As a result of these problems, numbers of this species in much of Europe, and particularly in Britain, are only now recovering from disastrous losses., where it is almost as common as the very numerous resident Brahminy Kite Haliastur indus.
In its breeding areas, like other harriers, it spends a lot of the day on the wing, although probably less than many other harriers. It flies higher than other harriers, usually at ten to fifteen feet, and in a less buoyant and easy manner, though it has the harrier habit of gliding with wings held well above the level of the back. Although it appears, probably due to its larger size, to fly slower than other harriers its hunting speed has been estimated at 31-36 miles an hour, faster than most harriers.
This harrier inhabits steppes and open marshes of a large part of Eurasia, from the Iberian Peninsula and England to Mongolia. It breeds also in Morocco. Its winter quarters are in sub-Saharan Africa. The population of the European Union amounts to about 6100 breeding pairs, which represent about 20% of the total European population. This species is shows wide fluctuations, but since several decades seems to decrease. The population for the western Palearctic is estimated at 35,000-50,000 pairs. The global population is unknown and could be anything between 150,000 to 200,000 individuals(Birdlife International, 2004). This uncertainty is due to the fact that most of the world’s population is situated in Russia and former Soviet republics where it is not quantified.
of Montagus harrier Circus pygargus males in south-east Poland