RSPB's Project Manager for Hen Harrier LIFE, Dr. Cathleen Thomas, provides an update on the class of 2017. Through a career in conservation, you have the privilege of working with some amazing wildlife, but you also have to face the reality that most individuals will never fulfil their full potential, due to the threats they face on a daily basis. As I’ve followed the journeys of the juvenile hen harriers in the class of 2017 , it’s been difficult to remain hopeful for our youngsters, in the face of an uncertain fate. First we lost Calluna , whose satellite tag transmissions stopped abruptly on 12 th August on a grouse moor in the Cairngorms National Park, then on 14 th August there was Mannin ’s failed sea crossing from the Isle of Man. I’m sad to report that we have now lost a further three birds. Sirius was a male hen harrier, who along with his sister Skylar was one of three chicks to fledge from a nest in Argyll, on land owned and managed by Forestry Enterprise Scotland in July 2017. Sirius and his siblings were the first offspring to be produced by our female, DeeCee, who fledged from Perthshire in 2016. On 11 th October, our Investigations team monitoring Sirius’ tag saw that he had stopped moving. The team carried out a search and were able to locate and recover his body from a hillside near Loch Lomond. He was taken to the veterinary laboratory for post-mortem tests and we’re still awaiting the results, which we will share in due course. We now also have two missing birds. Manu was one of two male hen harriers to fledge from a nest in the Scottish borders this summer. He explored the area around his nest for a few weeks before moving to the Northumberland coast in early August. His tag data showed that he quickly moved back inland to explore the uplands of Northumberland, where he was also seen several times in the field by local raptor workers. In mid-September, Manu moved west towards the Cumbrian border. He settled in an area of moorland near Denton Fell, and was briefly joined by one of our 2016 satellite tagged birds from the Cairngorms, Harriet. Manu’s tag was functioning perfectly, with his last known fix at 09:58 on 18 th October on Blenkinsopp Common, before transmissions abruptly and inexplicably stopped and we haven’t received any transmissions since. Northumbria Police were informed but their enquiries have so far yielded no leads as to what might have happened to Manu. Our Investigations Team searched around the area of Manu’s last known location, but found no sign of him. We have now put out an appeal for information, alongside Northumbria Police and the Northumberland Hen Harrier Protection Partnership, and urge anyone with any information to come forward. Manu (image by Tim Jones) A map of Manu's final journey We then also lost Tony. He was one of three chicks to fledge from a nest at HM Naval Base Clyde’s Coulport site in July this year. The security at the base that protects the submarine service also provides a sanctuary for hen harriers and the local MoD Police help to monitor nests, alongside experienced local raptor workers. Tony was named by MoD Police Officer John Simpson, in memory of his brother. After fledging, Tony headed west towards Dunbartonshire, where he spent some time exploring central Scotland. In early September, he headed down to south Wales, then he continued on to Cornwall. We then watched in awe as he continued his journey southwards and on 23 rd September, he began a long journey, heading south away from the UK and over the next five days Tony travelled through the Brittany region of France, across the Bay of Biscay and ended up in the Galicia region of Spain. Tony’s tag was functioning perfectly, with his last known fix on 22 nd October on a peninsular west of Cambados, before transmissions abruptly and inexplicably stopped and we haven’t received any transmissions since. Tony (image by Dave Anderson) A map of Tony's final journey By satellite tagging birds, we can build up a picture of the lives of hen harriers, yielding new insights into their behaviour and identifying their roosting and foraging areas, but they also allow us to learn more about the fates of these birds. In cases like Sirius, the tag is a powerful tool that allows us to locate the body so it can be sent for a post-mortem and we can investigate the cause of death. However for Manu and Tony, it is sad and frustrating that tags that are functioning perfectly suddenly and inexplicably stop, and we may never find out what happened to them.