Montagu’s Harrier Male “AU” Drives Rare Breeding Success at a Secret English Farmland Site

A single adult male Montagu’s harrier, leg-ringed “AU,” fathered six chicks this year by nesting with two females in two nearby nests on private farmland in England. This is the first back-to-back successful Montagu’s harrier breeding in the UK since 2019.

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Montagu’s harriers are the UK’s rarest bird of prey, placed on the conservation “red list” in 2021. The species peaked at roughly 30 breeding pairs in the mid-1950s, fell to zero pairs in 1974, and recovered to about 13 pairs in the late 2000s. No breeding evidence was recorded between 2020 and 2024.

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• AU – the only known breeding male in the UK.

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• Mark Thomas – Montagu’s harrier species lead at the RSPB.

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• RSPB – coordinating monitoring, fencing, and satellite-tagging.

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• Local farmers – providing habitat patches and protecting the nests.

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• AU has been credited with at least 16 chicks since 2018, including four in 2025 after a six-year gap.

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• Six juveniles fledged this year: three from each nest.

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• Satellite tags (£3,000 each) were attached to two female juveniles, tracking their ~7,000-mile migration to West Africa.

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• Historical figures: ~30 pairs (mid-1950s), 0 pairs (1974), up to 13 pairs (late 2000s), nine successful nests (2011).

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RSPB fieldworkers reported AU’s aerial courtship displays, known as “skydancing,” in early May. An RSPB spokesperson emphasized the species’ sensitivity to disturbance and kept nest locations secret to protect the birds.

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Mark Thomas highlighted the RSPB’s effort to rescue the species and expressed delight at the six flying juveniles. He noted that the satellite-tagging initiative will provide insight into migration routes, survival rates, and future return patterns.

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• “We are doing our absolute utmost to save this iconic species in the UK and are delighted with six flying juveniles this year.” — Mark Thomas, RSPB

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The breeding success at a concealed site shows the effectiveness of farmer partnerships, habitat management, and tracking technology. Monitoring juvenile movements across continents helps assess survival challenges during migration and refine protection measures for future breeding seasons.

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The satellite-tagged juveniles will be followed on their return to West Africa, informing future breeding site selection and timing. The RSPB will keep the nesting area secret and continue fencing and predator-exclusion measures with landowners.

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