The warden at the reserve has described the birds’ disappearance as a “devastating loss”, and the police said as a result the nests the birds were servicing have both failed - the result being that any offspring would also have died.
The bird, known as the “sky dancer” because of its aerial gymnastics, is one of the rarest breeding birds in the country due to raptor persecution – largely by gamekeepers protecting grouse moors – resulting in the species being wiped out in the UK during the Victorian period.
Raptor persecution was made illegal in 1954, but has been continuing nonetheless, and since just 2018, 56 hen harriers are known to have been illegally killed or gone missing.
In 2020, a hen harrier recovery project established in 2002 by Natural England recorded its best year to date, with 60 birds fledging from 19 nests across the north of England.
The RSPB, which did not support the project due to the high risk the birds would be illegally targeted, described the recovery as “painfully slow”, and said: “The science is clear that illegal persecution remains the most serious threat to this species.”
PC Samantha O’Key, Cumbria Police force’s wildlife, rural and environmental crime co-ordinator said: “The two male birds were servicing nests, and as a result both nests have now failed.
“In 2020 another male bird went missing in suspicious circumstances. The male was servicing two nests and as a result both nests failed.
“These birds were in good health, in a perfect environment for them to thrive, with plenty of food. It is highly unlikely that the harriers have died of natural causes.”
Steve Garnett, the warden at RSPB Geltsdale said: “This is devastating news, for hen harriers, for our hard-working team here at RSPB Geltsdale and for everyone who is rooting for a better outcome for these birds.
“Each season, the joy of seeing these birds return to breed is always tinged with worry over what might happen to them while they’re hunting beyond the safety of our reserve.
“We can make sure they are safe when they are on our land, but of course, they are free to range more widely and we know that not everyone has the best interests of these birds in mind.”
He added: “Hen harriers are illegally killed every year, so we are bound to view these disappearances as suspicious.”
An RSPB spokesperson told The Independent: “Hen harriers are a threatened species in the UK, and legally protected. Yet they remain one of the most persecuted birds of prey in the UK and continue to be illegally killed, or disappear in suspicious circumstances, particularly on or near land managed for shooting.”
The high death toll comes as Natural England has said it is now considering a feasibility study for reintroducing golden eagles to England. Conservationists are concerned the eagles could merely become a new target for those people already killing huge numbers of birds of prey.
The RSPB spokesperson added: “Any feasibility study looking to bring back golden eagles to England will need to look at illegal raptor persecution across the UK and assess its implications for any potential reintroduction project.”
Anyone with information on the disappearance of the hen harriers is encouraged to contact Cumbria Police on 101 or Crimestoppers on 0800 555 111 or at www.crimestoppers-uk.org.
Alternatively call the RSPB’s confidential raptor persecution hotline on 0300 999 0101.