Key Takeaways
- A male Montagu’s Harrier (“AU”) successfully raised six chicks across two nests on an English farm, marking the second consecutive year of breeding at the same undisclosed site.
- This achievement is a rare conservation win for the UK’s rarest bird of prey, which was placed on the Red List in 2021 after breeding success plummeted from nine nests in 2011 to none recorded between 2020‑2024.
- Conservationists fitted two of the fledglings with satellite tags to uncover juvenile migration routes, wintering grounds, and return timing—information critical for future protection.
- The success relied on close collaboration with farmers, nest fencing to deter ground predators, and intensive monitoring by the RSPB.
- Climate change and earlier harvests increase the risk of nests being destroyed by farm machinery, underscoring ongoing threats despite the recent breeding boost.
Overview of the Conservation Success
The Royal Society for the Protection of Birds (RSPB) announced a notable breakthrough for the Montagu’s Harrier (Circus pygargus) in the United Kingdom: a single male, nicknamed “AU” by field staff, bred with two females and reared six chicks across two separate nests on an English farmland. This outcome represents the second year in a row that the species has successfully nested at the same, undisclosed location—last year four chicks hatched there. The event is especially significant given the harrier’s precarious status; it was added to the UK Red List of most at‑risk birds in 2021 after a steep decline in breeding activity.
Background on Montagu’s Harrier in the UK
Montagu’s Harrier is a slender, long‑winged raptor that traditionally nests on the ground, concealed among cereal crops and other low vegetation. Historically, the species was a regular summer visitor to British farmlands, but numbers have dwindled dramatically over the past decade. Between 2011 and 2020, recorded successful nests fell from a high of nine to zero, prompting conservationists to classify the bird as critically endangered in the UK context. The harrier’s reliance on agricultural habitats makes it particularly vulnerable to changes in farming practices and land‑use intensification.
Details of the Breeding Event
In the current breeding season, the male harrier established two nests approximately a few hundred metres apart, each tended by a different female. The first nest produced three chicks, while the second yielded another three, totalling six fledglings. RSPB staff, working under a licence to monitor the nests discreetly, confirmed that all six juveniles reached the fledgling stage and were observed taking their first flights. This output exceeds the average clutch size for the species and underscores the productivity of the breeding pair under favourable conditions.
The Role of the Male Harrier
Unusually for many raptor species, the male Montagu’s Harrier assumed the primary provisioning duty for both nests. Observers from the BBC, granted exclusive access to the site, filmed the male delivering prey items—typically small mammals and insects—to the nest sites. In a striking display of aerial coordination, the male would drop the prey mid‑air, prompting the female to roll upside‑down and snatch the food with her talons before returning to feed the chicks. This behavior highlights the male’s critical contribution to the chicks’ survival, especially given the energetic demands of feeding two broods simultaneously.
Collaboration with Farmers and Nest Protection
The success of the breeding effort was not achieved in isolation; it hinged on proactive partnership with the landowners whose fields hosted the nests. RSPB conservation officers liaised closely with the farmers, advising them on the exact nest locations and recommending temporary exclusion zones. Simple but effective measures—such as erecting low‑visibility fencing around each nest—helped deter ground predators like foxes and badgers. Farmers also adjusted certain field operations to avoid disturbing the nests during critical incubation and chick‑rearing periods, demonstrating how wildlife‑friendly farming can coexist with productive agriculture.
Feeding Behavior Observed by BBC
The BBC’s footage provided rare insight into the harrier’s foraging ecology. The male’s hunting technique involved low, gliding flights over the crop canopy, where he could surprise prey hidden among the stalks. Once captured, the prey was often carried aloft before being released for the female’s acrobatic catch. This mid‑air transfer reduces the time the female spends away from the nest, thereby minimizing exposure to predators and harsh weather. Such detailed behavioural data are valuable for understanding the species’ energy budget and informing habitat management strategies that support sufficient prey availability.
Migration Mysteries and Satellite Tagging
Despite extensive knowledge of adult harrier movements, the post‑fledging phase of juvenile life remains largely unknown. To fill this gap, the RSPB fitted two of this year’s chicks with lightweight satellite transmitters. These tags will track the birds’ inaugural migration to sub‑Saharan Africa, logging stop‑over sites, flight speeds, and duration of the wintering period. According to Mark Thomas, Head of Investigations at the RSPB, the data will reveal whether juveniles return to the UK in their first or second year—a crucial piece of information for assessing population viability and shaping conservation interventions.
Threats from Climate Change and Farming Practices
While the current breeding season is encouraging, experts caution that long‑term prospects remain fragile. Climate change has advanced the timing of the local grain harvest by roughly a month compared with historical norms, increasing the chance that mechanical operations will coincide with active nests. Because Montagu’s Harrier nests are concealed at ground level, they are especially susceptible to accidental destruction by tractors, combine harvesters, or other farm equipment. Additionally, shifts toward more intensive monocultures and pesticide use can reduce the abundance of the small mammals and insects that form the harrier’s diet.
Implications for Future Conservation Efforts
The successful fledging of six chicks offers a hopeful template for future recovery efforts. Key lessons include the importance of early nest detection, swift engagement with landowners, and the utility of protective fencing against ground predators. The satellite tagging initiative promises to generate actionable intelligence on juvenile survival and migration pathways, which can inform targeted habitat protection along flyways and in wintering grounds. Continued monitoring, coupled with agri‑environmental schemes that incentivize low‑input farming and retain habitat heterogeneity, will be essential to transform this isolated success into a sustained population increase.
Conclusion and Call to Action
The story of “AU” and his six offspring underscores both the vulnerability and resilience of the UK’s rarest bird of prey. While the recent breeding triumph is a cause for celebration, it also serves as a reminder that the species remains on the brink, confronting pressures from climate shifts, evolving agricultural practices, and habitat loss. Sustained vigilance, scientific research—particularly the forthcoming migration data—and collaborative stewardship between conservationists, farmers, and the wider public will be vital if the Montagu’s Harrier is to move from a rare success story to a stable, thriving component of Britain’s avian heritage. Continued public engagement, such as reporting sightings to the RSPB, further strengthens the network of eyes and ears needed to safeguard this iconic raptor for generations to come.