Picture of the Forest of Bowland, by Langden Brook, Sykes Fell, May 2002

Hen harriers have had a mixed breeding season in the Forest of Bowland, with good numbers of breeding birds, but low breeding success. Species and Habitats Officer, Sonja Ludwig, explains.

RSPB staff and volunteers recorded 10 nests on the United Utilities Bowland Estate during the 2024 breeding season.

Nine of these nests were successful, although only 22 hen harrier chicks fledged – an average of 2.4 young per successful attempt overall. The remaining nest sadly failed as the female deserted her eggs. Natural England also recorded an additional female nesting on a private estate in Bowland not monitored by the RSPB.

Hen harriers are one of the most iconic bird species nesting in our upland moorland habitats, but also one of the rarest and most threatened. For many years the Forest of Bowland has been the most important stronghold for breeding hen harriers in England, and the RSPB has been working in partnership with United Utilities and their tenants to monitor and protect these amazing birds on the United Utilities Bowland Estate.

Chick survival was much lower than in 2023, when 32 chicks fledged from seven nests - 4.6 young per successful attempt. This was due to the prolonged wet and cold weather during the hatching and early chick rearing period, likely combined with a lack of prey.

This was exacerbated by the fact that six nests were associated with polygamous males, which resulted in smaller brood sizes compared to the nests with monogamous males. Male hen harriers often mate with more than one female (known as polygamy), however, when prey availability is low, they may struggle to provide sufficient food for both broods. Females can compensate for reduced male provisioning by investing more time in hunting themselves, but that means leaving their young unattended and exposed to the elements.

RSPB staff fitted eight hen harrier chicks with satellite-tags on the United Utilities Estate to follow their movements and survival. Five tags were kindly sponsored by United Utilities.

Image credit Ivan Ellison 

The sustained recovery of hen harriers in Bowland during the last seven years is encouraging and a tribute to successful partnership working. However, the overall recovery of hen harriers in England still has a long way to go, as illegal persecution, changes in land use, habitat loss and climate change may continue to put their recovery at risk.

Cover photo: Forest of Bowland, by Langden Brook, Sykes Fell, May 2002 by Andy Hay (rspb-images.com)