The future for the Montagu's Harrier looks very bleak

In the course of the 20th century, the breeding population of the Montagu's Harrier (Circus pygargus) decreased dramatically in The Netherlands. In the first half of the century, it was a fairly common and widespread breeding bird in dunes, heathland, moors and marshland. The species has disappeared from large sections of the country from the 1950s onwards, with the exception of a temporal increase in newly reclaimed polders (Southern and Eastern Flevoland). In 1950-90, the population decreased from about 250 pairs to less than 10 pairs. At present, the species is on the verge of extirpation. Food availability has decreased, resulting from detrimental changes in farming practices. The Montagu’s harrier preys on small birds, voles, shrews, rabbits, lizards and insects. In recent decades, large-scale spraying of pesticides in some African wintering areas may have added to the negative trend. The future for the Montagu's Harrier looks very bleak indeed.

Sources:
Zijlstra M and Hustings F. Limosa 65 (1992): 7-18
RSPB
https://www.rspb.org.uk/birds-and-wildlife/bird-and-wildlife-guides/bir…