Agricultural development has resulted in fragmentation of the Pallid Harrier's former core breeding range and has caused a population decline. This has been particularly noticeable in Eastern Europe, west of the Volga River. At the same time there have been instances of breeding in new areas, mostly far north of the range indicated in the standard handbooks. Most breeding pairs shift nesting places from year to year, probably tracking changes in the abundance of small rodent prey. Thus, local fluctuations in the Pallid Harrier population and range movements have hampered survey work. A preliminary assessment of the total breeding population of the Pallid Harrier at the beginning of the XXI century is 9,000 - 15,000 pairs, and it is evidently in decline. There is an urgent need for a structured program of surveys, research, monitoring and conservation action at breeding grounds. Reliable records of the species on migration routes and on winter grounds are also difficult to obtain due to the rarity of the species, its broad-front migration strategy, and difficulties in field identification. Further survey work and research is needed on this species in the winter range in order to be able to target conservation action effectively. However, some important concentrations have already been located in India and Africa where strict conservation measures are required now.
In Europe the breeding range is highly fragmented and its western limits shift from year to year. At the same time there is some evidence of recent expansion of Pallid Harriers to the north, due either to a shortage of typical humid habitats in the south or as a result of long-term fluctuations of the species' breeding range.

Wetlands and other humid areas amidst grasslands of steppe and forest-steppe are the typical habitat of the Pallid Harrier. These habitats still exist in southern Russia and Kazakhstan. However, many of these habitats have been developed or cultivated. Pallid Harrier rarely nest in agricultural fields, although it can use them apparently without difficulty in years of good food abundance. The limiting factor in this habitat is therefore probably the food availability (food being in general less available in agricultural fields). The preferred breeding habitats in the steppe are wet grasslands close to small rivers and lakes, and marshlands. The Pallid Harrier can even nest in swamps or moist islands on lakes. More recently, it has been noted to colonise clearances and other openings in forests in the north. The Pallid Harrier breeding range consists of three zones. They are: (1) the optimal one (mostly humid habitats in steppe, forest-steppe and semi deserts upon Northern Eurasia); (2) areas of sporadic breeding (a forest zone in Europe and northern desert grasslands in Kazakhstan; (3) incidental breeding during invasions of northern, central and even western Europe.

The Pallid Harrier nests both solitarily (mostly in the north) and in loose groups of 3-5 pairs (in pristine humid grassland habitats), sometimes close to Montagu's Harrier's nests. Nests are on the ground, in both tall (over 50 cm) and shorter grass, and in swamps. Nesting distribution shifts from year to year depending on the abundance of small mammals. However, in the most suitable habitats some breeding sites can be used for a succession of years. The typical clutch is of 4-5 eggs incubated for 30 days, from which 2-3 young fledge in 35-40 days. The female incubates the eggs and broods the nestlings, while usually the male provides food for them.

Small mammals and birds (mostly larks and pipits) are the preferred prey, at least in summer. Pallid Harriers are thought to search for areas with high densities of small mammals in early spring. Alternative foods are lizards and large insects (mainly locusts and grasshoppers). Small passerine birds (mostly larks) and orthoptera are important prey during migration and on wintering grounds. As harriers forage far afield from their roosts (up to 20+ km) by day, land uses over a wide area around roost sites (in the roost 'catchment' areas) are therefore relevant and lead us to adopt the 'landscape', as opposed to the 'island' perspective, on winter harrier conservation. Grasslands and thorn forest are known to be important to Pallid Harriers for hunting in India. Preferred habitats in parts of Africa include both grasslands and croplands. The Pallid Harrier has a number of structural characteristics consistent with adaptation to catch agile prey, especially small birds. Observation of males early and late in the day in the surroundings of the big roost site at Velavadar in India, has shown that hunting flight is fast, low and direct, using the stands of taller grass to steal up on flocks of larks feeding on the ground. Habitat structure is, therefore, important and at risk from overgrazing or excess harvesting. Territorial behaviour has been observed between males, probably limiting the carrying capacity of prime foraging habitat. In Africa, precise knowledge of diet is still required. In several accounts from Africa it is said to hunt near grass or savanna fires.

Circus macrourus breeds primarily in the steppes of Asiatic Russia, Kazakhstan and north-west China. Small populations breed in Azerbaijan, Romania, Turkey and Ukraine. A minority winter in south-east and central Europe, north Africa and the Middle East but most migrate to the Afrotropics (Sudan, Eritrea, Djibouti, Ethiopia, Somalia, Kenya, Uganda, Rwanda, Burundi, Tanzania, Malawi, Zambia, Zimbabwe, Mozambique, Chad, Niger, Mali, Senegal, Gambia, Sierra Leone, Guinea-Bissau, Liberia, Ivory Coast, Ghana, Togo, Benin, Burkina Faso, Nigeria, Cameroon, Central African Republic, Democratic Republic of Congo, Angola, Namibia, Botswana, Swaziland and South Africa) and the Indian subcontinent (Afghanistan, Pakistan, India, Sri Lanka, Nepal, Bangladesh and Myanmar).There are also records from the Maldives. The global population is estimated at 9,000-15,000 pairs, having shown marked declines and range contractions. The status of the European population (310-1,200 pairs in Azerbaijan, Romania, Turkey, Ukraine and western Russia, occupying 25-49% of the global breeding range) was recently reassessed1. Following a large decline in Europe during 1970-19907, when up to 30% of birds were lost (particularly from the key population in European Russia), the species continued to decline in 1990-2000, and overall trends exceeded 30% over three generations (18 years). It appears that the species has been extirpated from Moldova and Belarus, where it bred formerly. In Asia, however, the population is presumed to be more stable. Surveys in the Kustanay Oblast region (northern Kazakhstan) from 1997 to 2004 indicate a fluctuating but ostensibly stable population of 1,500-2,000 pairs, nesting at a density of 9.4-25 pairs per 100 km2. No other detailed surveys are known from the species's Asiatic range, although anecdotal evidence from eastern Kazakhstan (Almaty to Chockpack Bird Station) suggests that it is locally abundant. Assessment of the status of this species is complicated by the fact that on breeding territories numbers fluctuate in response to environmental conditions, probably numbers of small mammals. Thus, high or low numbers in any given year or two year period may be indicative of change in demographics or they may be indicative of change in local environment (and birds may go elsewhere without their population size changing). Reliable records from migration routes and wintering grounds are also difficult to obtain owing to the rarity of the species, its broad-front migration strategy, and difficulties in field identification, although important concentrations of birds have been identified in parts of India and Africa.

The Pallid Harrier is a broad-front migrant that does not concentrate through mountain passes or on short sea crossings, as many other raptors do. This broad-front migration strategy protects the Pallid Harrier from shooting and other problems met by many other raptors at such migration bottlenecks. European populations of the Pallid Harrier migrate mostly to Africa. Migrants were recorded in 36 countries and recently recorded through 12 raptor migration sites: Bab-el-Mandeb Strait in Djibouti, Suez Canal in Egypt, Lake Langano in Ethiopia, Tsavo and Lake Ololokwi in Kenya, Niger Valley in Mali, Akagera in Rwanda, Mti Mwili and Lake Manyara in Tanzania, Cape Bon in Tunisia, Lundazi and Lake Chvego in Zimbabwe.
The principal wintering grounds of the Pallid Harrier are open country throughout the Indian subcontinent, the savanna belt in Africa south of the Sahara, and the East African steppes. The Pallid Harrier occupies this vast distribution area during the northern winter, from October to March, and shares it with (the generally more common) Montagu's Harrier. Because of plumage similarities, it is difficult to differentiate between these two species in the field, especially female and juveniles. They also mix at the same night roosts. Roost site conservation measures (mainly in grasslands) will therefore benefit both, but it is important to be aware that they can occupy different foraging niches.
By day, harriers are very mobile, widely dispersed and therefore difficult to count. However, their use of communal night roosts in winter enables counts to be made. They roost on the ground, typically in favoured patches of rank ground vegetation at traditional sites in natural or semi-natural habitats such as grassland and marshes, but occasionally on bare ground. The largest one reported was of 'hundreds' of migrating harriers roosting in grassland in the SE Serengeti near Mti Mwili, Tanzania in March 1998.