Bison, which weigh the size of a small car, conceal their pregnancies to avoid being targeted by predators which is why staff at the project didn’t realise the female bison was expecting.
So, when a little female calf was born it took the rangers completely by surprise.
Although discovered on Friday 9 September, due to the Queen’s death and the period of mourning the birth was not announced immediately by Kent Wildlife Trust or Wildwood Trust.
Rangers say she has developed well, playing in the rain and copying the other bisons’ iconic dust-bathing behaviour.
The new baby’s appearance means there are now four female bison in the woodland at West Blean and Thornden Woods.
The birth was an unexpected surprise for Bison Rangers Tom Gibbs and Donovan Wright.
Tom said: “It is difficult to detect pregnancy in bison as they naturally conceal being in calf to avoid being hunted by predators, it is a survival mechanism.
“Though it was a surprise to see that the younger female bison had given birth, it was always a possibility, and we have created a care plan for the calf to ensure her needs are met. These animals are wild, so we want to remain as hands-off as possible, but their welfare is at the absolute heart of what we do.
"She is being observed by experts and we are constantly monitoring the whole herd to ensure their wellbeing. We always hoped that the bison would breed, but it is fair to say we were not anticipating it quite so soon.”
Bull to be introduced soon
A bull is also due to be introduced in the next two months as part of The Wilder Blean Project, a wilding initiative to help combat the climate and biodiversity crises.
Bison act as ecosystem engineers, creating light and space for wildlife to thrive through their natural behaviours.
Tom said: "We are also preparing for the arrival of a bull from Germany within the next few-months so we will be carefully planning how that introduction is made to ensure they bond well and act as a herd should.
“This is now an incredibly important time for this family of eco-system engineers and we understand that people will want to catch a glimpse of this new addition, however we ask people to consider the impact they may have and ask that they are given the space and time they need to bond.”
The first phase of the Wilder Blean Project was enabled through funds raised by players of People’s Postcode Lottery Dream Fund.
An exciting development with an incredible species
While remains of European Bison have not been discovered in the UK, they have been found under the North Sea. The site, known as Doggerland, was once a land bridge connecting the UK and the continent.
A close relative of the European bison, Bison schoetensacki, did however live in the UK around 6,000 years ago before becoming globally extinct. By the early 1900s, European Bison were also on the brink of extinction and could only be found in two protected areas - in the former Soviet Union and in Poland.
The herd of European bison species is part of a £1.1 million ‘rewilding’ scheme led by the Wildwood Trust and Kent Wildlife Trust (KWT).
Paul Hadway, Director of Conservation of Kent Wildlife Trust said: “This is an exciting development within a pioneering project. European Bison are an incredible species, which were on the brink of extinction after the first World War.
"To think that their numbers now swell beyond 9,000 is a true testament to the commitment and dedication of international breeding efforts and, as an organisation, Kent Wildlife Trust are privileged to now be part of that journey."
Creating a biodiverse environment
Natural bison behaviours – grazing, dust bathing, eating bark and felling trees – enable other species to thrive. It is hoped the presence of bison at the 120 acre Blean site, alongside Exmoor ponies and Iron-Age pigs, will transform the woods into a lush, thriving, biodiverse environment once more and allow less hands-on management.
Since their release in July, the matriarch from Scotland has bonded well with the two younger females from Ireland. The matriarch leads the herd, often giving the young females the confidence to explore the woodland and source new food.
Mark Habben, Director of Zoo Operations at the Wildwood Trust, said: "When the bison took their first steps into the wild just weeks ago, it was hard to imagine that anything could come close to the elation we felt in that moment. But here we are celebrating the arrival of a bison calf.
"Ground breaking projects like this, by their nature, always carry an element of the unexpected but this addition to the herd has come as a significant surprise, albeit a very welcome one.
"Unlike domestic cattle, bison show very few signs of pregnancy and it is not uncommon for them to travel without impact to their welfare. When the herd arrived they were calm and settled quickly, a sign that the transportation process had not put them under significant duress.
‘We are delighted that mother and calf are both doing well and look forward to watching the herd continue to grow and flourish in the coming months."