The first formal description of Montagu's harrier was by the Swedish naturalist Carl Linnaeus in 1758, in the tenth edition of his Systema Naturae, under the binomial name Falco pygargus.

Compared with other harriers this species has characteristic black bands along the secondaries, both above and below the wing and rusty streaks on belly and flanks.

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.

The Montagu's harrier has a particularly graceful flight, with powerful and elegant wingbeats which give an impression of buoyancy and ease.

In true harrier fashion it searches the countryside, flying low, and generally holds its wings with a marked positive dihedral.

The distinction between female pallid and Montagu's harriers is the most delicate and can only be made in good conditions as the proportions are similar.

The best recognition character is the pale collar around the neck of female and juvenile pallid harriers which is not present in the Montagu's.

This species can be found in a middle-latitude band of predominantly temperate climates, but also in Mediterranean, and boreal zones.

[citation needed] In short, for breeding the Montagu's harrier requires a large open area, with sufficiently tall ground vegetation to afford cover without being overgrown.

It favours posts on which both male and female can rest and survey the breeding area: these can be fenceposts, small trees, or rocky outcrops.

In areas where the food supply is composed almost exclusively of rodents, the breeding success depends greatly on the cyclic fluctuations of vole populations.

One site, Estuary Farm, near North Wootton in west Norfolk, a special observation area was negotiated with local landowners, so that pressure could be taken off other nesting pairs.

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.

This is due to several negative factors: first, the massive use of agricultural pesticides such as DDT and other environmental poisons was extremely detrimental to the harriers themselves, as well as rarefying their prey, in particular large insects.

The modification of agricultural practises, with an evolution towards more intensive farming also puts pressure on harriers, with faster growing crops preventing those birds that nest in farmlands from finishing their nidification before their clutches are destroyed by harvesting machines.

These local trends show that while they have access to suitable habitats and food supply there can still be positive developments.

Reproduction begins with the return of both partners to the nesting site, at which point both male and female will start displaying.

Montagu's harriers breed for the first time when two or three years old, but occasionally one-year-old females may attempt to nest.

Birds from Eurasia spend the winter in sub-Saharan Africa, while those from the eastern part of the range migrate to the Indian subcontinent.

[14] Spring return peaks in April, and most birds have arrived by May though there is evidence that first-year juveniles spend their first summer in the winter quarters In western Europe, an estimated 70% of breeding pairs nest in agricultural farmlands, especially cereal crops.

Once a nest is spotted in a field, it can be safeguarded either by relocating it to a safer area or by creating a protected space which will not be harvested.