Arguably our rarest breeding diurnal bird of prey, Montagu's Harrier is an exclusively summer visitor and one associated with drier habitats than our other breeding harrier species.
Britain is on the north-west fringe of the Montagu's Harrier's European breeding range, holding just a very small number of breeding pairs annually. This wider distribution suggests that we should be able to support more pairs, implying that lack of suitable habitat or other factors may be limiting.
While there are some areas within Britain that have held pairs over many years – for example the open arable farmland of Wiltshire and neighbouring counties – atlas data suggest a more fluent pattern of settlement.
Select a topic for more facts and statistics about the Montagu's Harrier
Harriers are stunning, lithe and elegant birds of prey. Two species of grey harrier are regularly found in the UK, Hen and Montagu's - the males are relatively easy to separate, but the females and young birds can be more tricky.
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The Montagu's Harrier is an extremely rare breeding species in the UK and the population has decreased strongly over the 25 years to 2019; in 2019 only two pairs were present and only one pair bred (Eaton et al. 2021). Breeding numbers have previously fluctuated: After having peaked at around 30 pairs in the mid-1950s they decreased and there were no pairs in 1974, before numbers improved again to a maximum of 13 pairs in the late 2000s (Balmer et al. 2013).
Montagu's Harrier is an increasingly rare summer visitor, arriving from April onwards.
Weekly occurrence patterns (shaded cells) and reporting rates (vertical bars) based on BirdTrack data. Reporting rates give the likelihood of encountering the species each week.
Movement
Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.
An overview of year-round movements for the whole of Europe can be seen on the EuroBirdPortal viewer.
Foreign locations of birds ringed or recovered in Britain & Ireland
Encountered in:
Winter (Nov-Feb); Spring (Mar-Apr); Summer (May-Jul); Autumn (Aug-Oct)
Biology
Lifecycle and body size information about Montagu's Harrier, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.
Pesticides and a drought in the Sahel which began in 1968 may have driven the declines in the late 1950s and 1960s (Clarke 1996). Numbers have never recovered fully and, with Montagu's Harriers often nesting in agricultural crops, local action and monitoring can be important to support and protect nests and young (Clarke 1996, Balmer et al. 2013).
Over 2,000 km² of Belarus previously given over to intensive agriculture and dense settlements was affected by the 1986 reactor meltdown at the Chernobyl Nuclear Plant in Ukraine.
Links to more studies from ConservationEvidence.com
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