Introducing Grayse and Mannin, the satellite-tagged Manx Hen Harriers

Thanks to the combined efforts of conservation charities, businesses and dedicated individuals, two young Hen Harriers on the Isle of Man have been successfully fitted with satellite trackers, known as tags, as part of efforts across the British Isles to protect the species.

The detailed movements of sibling Manx Hen Harriers, Grayse and Mannin, are now being closely monitored by scientists. Until recently, little was known about the seasonal or lifetime movements undertaken by Hen Harriers. By tracking birds in the Isle of Man and across the British Isles, conservationists hope to gain a better understanding of the species’ behaviour. The insight gained will enable more effective protection measures and conservation strategies to be put in place.

Hen Harriers: Mannin (L) and Grayse (R) (James Leonard)
Hen Harriers: Mannin (L) and Grayse (R) (James Leonard)

Last year, Aalin, a young female Hen Harrier was tagged. She was tracked leaving the Isle of Man in late summer, then spent the winter in Shropshire before partnering with a male in the Welsh hills during the summer of 2017. After just one year, Aalin’s adventures already tell us that any conservation efforts must be joined up across different territories – and coordinated by the different authorities responsible for the many locations on which the birds might depend during their lifetimes.

The Hen Harrier is an iconic part of the Manx avifauna. This Buzzard-sized, swift and graceful predator is a regular spectacle in the Manx uplands during the summer and along the coasts and lowlands in winter. According to research by Manx BirdLife (funded by the RSPB and DEFA), in 2016 there were 30 active nests on the Island. “This is half the size of the population just over ten years ago and it is important for us to understand the reasons behind this decline” said Neil Morris, Managing Director of Manx BirdLife, who continued, “Tracking the species’ movements will aid our understanding of how to safeguard the Island’s population of this magnificent bird of prey.”

The tagging of Grayse and Mannin is part of a wider programme coordinated across the British Isles by the RSPB’s Hen Harrier LIFE+ Project team. In the Isle of Man, Louise Samson, DEFA’s Forestry Warden played the leading role in monitoring nesting Hen Harriers, with input from Manx BirdLife’s Emma Naldrett. Louise located the nest with Grayse and Mannin in the uplands of the Isle of Man, to which James Leonard, a trained and licensed volunteer tagger, travelled from Scotland in order to tag the siblings.

Louise observes, “Hen harriers have become an integral part of the beauty of the Manx uplands appreciated by both local and visiting wildlife enthusiasts. Satellite-tagging a brother and sister will enable us to watch these birds through their life journeys and monitor their habitat use, movements and interactions with each other as well as with other Hen Harriers.”

From September, those interested will be able to follow the progress of these special birds along with a number of other Hen Harriers as the RSPB charts their progress on the Hen Harrier LIFE+ project website. Visit or follow the project on twitter @RSPB_Skydancer.

Manx BirdLife is especially grateful to John Francis and the Tesco ‘Bags of Help’ scheme and to the Isle of Man Steam Packet Company for their support of the project. The team also wishes to thank all those shoppers who voted in support of the project using their blue tokens in Tesco’s Douglas store.