By James Bray and Niall Owen

For several years now, satellite tags have been providing the RSPB with vital – and often surprising –  data on how and where hen harriers live. This is the story of two remarkable hen harriers, Bomber from Wales and Apollo from Lancashire, who have reset our expectations of what these remarkable birds can do.

Apollo being tagged as a youngster in 2019 as part of the Hen Harrier LIFE project

Initially we believed that most of our tagged hen harriers stayed in the British uplands all year-round. However, it’s become clear that around 10% of birds cross the English Channel for the winter, some bound for France and a few for Spain. And none of the tagged RSPB birds that travelled to Spain made it back to the UK.

Meet Apollo. Apollo fledged from the United Utilities Bowland estate in Lancashire in 2019. The RSPB works in partnership with United Utilities, their farming and shooting tenants, and the AONB, to protect close to a third of England’s hen harrier breeding population. After leaving Bowland, this Lancashire-born male flew almost 1000 miles to Portugal, then on to Extremadura in Spain – a landscape of steppes, forest and farming west of Madrid, and one of the most biodiverse places in Europe. Our last blog had us wondering whether he would return to the UK to breed. By April 2020, all other Bowland birds had returned, so our expectations for Apollo were low. But late in April, incredibly, he left his Spanish wintering ground and made the long, perilous journey north.

Apollo flew across the Bay of Biscay, the sea crossing taking him two days. He then flew straight through northern France and was soon making his way through the Welsh hills, where he spent a few days making short jumps (possibly feeding, possibly looking for a mate). On 15 May 2020 he arrived back in Bowland and settled down to breed with a young female just a couple of miles from where he hatched.

Apollo's route

The pair nested on a private estate; to our knowledge the first nest on a private estate for ten years. It was great to see them welcomed by the estate and this nest will hopefully be the start of the species recolonising areas of Bowland where they haven’t been breeding for a long time.

Apollo brought in plenty of food in but only one chick fledged. Disappointingly, this chick’s satellite tag signal disappeared near the nest not long after fledging. Neither tag nor bird were found.

Come October 2020, Apollo was on the move again. Incredibly, he headed in a dead-straight line back to Extremadura, and to the exact-same place that he spent last winter.

Bomber in flight (photo by Niall Owen)

This is Bomber. Named for her ring number (B2) and sheer size, she fledged from the Migneint, Snowdonia in July 2019, and in October began the first leg of an epic round-trip. Her tag allowed us to track her as she crossed the Channel and continued south, settling in the Navarra region of northern Spain for the winter. This was even more remarkable, because most female hen harriers tend not to wander far from where they hatched.

In spring 2020, Bomber embarked on her return journey home, arriving to north Wales on 9 May 2020, already some way into the typical breeding cycle of hen harriers. She quickly established herself in an area of the Carneddau range, around 25 miles from her natal site. Not all hen harriers breed in their first year, however Bomber paired up with an adult male, but sadly none of their chicks fledged.

Bomber appeared to spend the autumn bettering her hunting skills, and on 3 November – a month later than in 2019 – she flew south and was back in her winter territory by the 18th. She had covered almost 1000 miles in just over two weeks.

Winter-site fidelity has been shown in a number of bird species, but hen harriers have a reputation for wandering, making the stories of Apollo and Bomber absolutely fascinating – and something we would never have known were it not for satellite tagging. By contrast, Apollo’s brother Dynamo has not gone further than 50 miles from Bowland over the course of his life!

The longer these birds live, the more amazing stories they tell us. It looks like, at the moment, our tagged hen harriers are surviving longer than before which is, of course, a very welcome development.

The UK hen harrier population has declined in recent decades, largely due to human persecution, making every returning hen harrier a beacon of hope for the future. We’re very excited by what spring 2021 may bring and desperately hope that both Apollo and Bomber make it back to Britain to nest again and safely rear a brood. Hopefully, a year older and wiser, these brilliant birds will go on to raise a family and send a new intrepid generation out into the world.

Bomber's route