A sighting of one of the UK’s rarest birds in a forest on the outskirts of St Albans has got local twitchers all of a flutter.

Members of the Woodland Trust at Heartwood Forest in Sandridge were treated to a surprise guest appearance from a hen harrier – which hasn’t been spotted since the charity first begun developing the site in 2008.

The hen harrier is a bird of prey that breeds throughout the northern parts of Canada and the USA and migrates to more southern areas such as southern Europe and Asia in winter.

Volunteer Murray Brown, who saw the bird at Christmas time, said: “Hen harriers are very rare passage migrants and winter visitors to Hertfordshire and this bird may have arrived from the continent to take advantage of our relatively mild winters.

“In the UK, hen harriers are threatened as a breeding species as they are still illegally persecuted by grouse-shooting interests.

“Three English nests were successful in 2014 due to 24 hour protection but in 2013, hen harriers failed to breed in England at all.

Site manager, Louise Neicho, said: “The arrival of the hen harrier, along with the presence of short-eared owls, barn owls, little owls, red kites, buzzards and high numbers of kestrels also shows that there are plenty of small mammals on site too.

“The diversity of wildlife is great for visitors to see and also demonstrates the value of the habitats we’ve helped improve.”

So far more than 460,000 trees have planted at the site and visitors are invited to the next public planting events on March 14.

To find out more visit www.woodlandtrust.org.uk/heartwood