Montagu’s harriers, Britain’s rarest bird of prey, have failed to breed in the UK for the first time in 45 years, conservationists have said.

A report shows that the migratory bird, a close relative of the also rare hen harrier, failed to breed in the UK for the first time since 1975 in 2020 – the most recent year for which the data is available.

Only three females and six males were reported, and none formed a pair, according to the annual report from the Rare Breeding Birds Panel which is funded by the Government’s Joint Nature Conservation Committee (JNCC), and wildlife charities the RSPB and British Trust for Ornithology (BTO).

The report, which recorded 101 scarce or rare native birds that bred and 12 non-native ones in 2020, reveals better news for other species, including common cranes and white-tailed eagles which reached record highs.

Goshawks, another rare bird of prey which faces persecution, are still managing to prosper, the report shows.

Rare Breeding Birds Panel secretary Dr Mark Eaton said it was “pretty serious” for the Montagu’s harrier.

But he said: “There are quite a lot of these rare species doing well, and they are a demonstration of how conservation can work, so the increase in cranes, and the return of the white-tailed eagle to the point it is not on the red list any longer.”

Montagu’s harriers were driven almost to extinction in the 19th century by persecution, and also disappeared in the 1970s due to the impacts of pesticides on nature, conservationists said.

They spend just a few months of the year in their European breeding grounds, wintering in Senegal, West Africa, and are at risk from threats in many countries as well as extreme weather and illegal hunting on their migration routes.

They nest in agricultural fields, such as winter cereals and oil seed rape in the UK, where intensive conservation efforts are needed to protect them from farming activity, reduce predators and prevent disturbance.

They also need protection from the possibility of illegal persecution, which is suspected to be an issue.

Montagu's harrier (Mark Thomas/PA)
Montagu’s harrier (Mark Thomas/PA)

Dr Eaton said: “It’s pretty serious. They’ve always been a rare bird in the UK, and over the centuries they’ve gone up and down and got close to disappearing in the past.”

The fact they migrate from Africa to Europe means there is hope some birds could return in the future, and conservationists and volunteers are ready to help protect them in the UK, though there is nothing they can do if they do not turn up to attempt breeding, Dr Eaton said.

But he said: “Although the Montagu’s harriers are a really worrying thing, there is quite a lot of good conservation going on that’s helping these rare birds.”

Birds including spoonbills, bitterns, great white egrets and cattle egrets have been hitting a new high total each year in recent years.

Some birds are benefiting from the creation of new wetland areas such as the Avalon marshes in Somerset, as well as protection and conservation in Europe, so they have bigger populations that can spread to the UK.

And some species such as cattle egrets, originally from Africa and mainland Europe, are now benefiting from climate change and moving their range north.

Dr Eaton warned that climate change would ultimately be bad for a lot of wildlife, with species of northern Britain set to suffer as temperatures rise.

But so far, one bird, the red-necked phalarope which is found in northern Scotland and which might be expected to stop breeding in the UK, the southern end of its range, in the face of climate change, is bucking the trend and reached new highs in the latest report.