Wild Isles Episode Three: Grassland premieres at 7pm on Sunday 26th March on BBC One and iPlayer.

Our grasslands are some of Britain and Ireland’s most beautiful places. From the coastal flower meadows in the Scottish Outer Hebrides to the rich open landscapes in the mountains of south-west Ireland, we enter surprising and dramatic worlds inhabited by creatures great and small.

Interview with producer Nicholas Gates

What would you hope that the audience will take away from watching the series?

A sense of how remarkable, how important and how threatened the nature that we have here in Britain and Ireland is and a desire to help ensure that it is allowed to recover. We want the audience to see the extraordinary side of some of our most familiar creatures.

Why are Britain and Ireland globally important for nature?

Our unique geographical placement in Europe, being situated both in the global north but also surrounded by seas, keeps our climate warmer than places of equivalent latitude around the world. This makes it extremely attractive to migratory species, particularly summer migrating insects and birds arriving to breed from the south, and winter migrating birds arriving to feed from the north.

How was it travelling around the British Isles for this series?

I am a lifelong British naturalist, so for me personally it was hugely eye opening to visit some of our most remote and important wilder places. Travelling to so many of these over the course of three years filming allowed me to see the different approaches to conservation being taken throughout our isles and meet the exceptional people dedicating their lives to protecting some of our rarest species. As all our locations on Grassland could be driven to, we spent many, many hours on the road, which highlighted just how many places in Britain and Ireland could be improved for nature in the future.

This episode includes the first time the lifecycle of the large blue butterfly has ever been filmed in full, can you tell us about how you filmed this?

The lifecycle of the large blue butterfly is extremely complex, with many intricate steps required for the egg to successfully make it through to an adult butterfly. Filming each of these steps was only possible by working closely with a team of three expert scientists (Professor Jeremy Thomas, David Simcox and Sarah Meredith) who were responsible for reintroducing the large blue butterfly at a number of locations throughout Somerset and Gloucestershire. We split the filming into many different shoots and just worked on one stage of the butterflies’ lifecycle at a time. The hardest step of all to film was the exact moment when the caterpillar successfully tricked a worker ant into picking it up and carrying it back to the nest.

And you filmed the “witch bee”, a species which nests in old snail shells and looks like she’s riding on a tiny broomstick as she carries sticks for the nest?

There are more than 250 different species of bee in Britain and Ireland*, which live in a wide mix of places, from woodworm holes in deadwood for our smallest species, the tiny scissor bee, to old vole nests for our largest bumblebees. But of all these species, we felt there was one which really stood out for her persistence in finding just the right nest for her youngsters. The two-coloured mason bee, our “witch bee”, whizzes around chalk grasslands looking for empty snail shells of the exact right size. Like Goldilocks with her porridge testing, the female two-coloured mason bee will check lots of empty shells in the grassland, some are too big, some are too small or damaged, until she finds just the right one within which to lay her egg. She is nicknamed the “witch bee” as after laying each egg she seals up the shell and then hides it under a pile of tiny sticks. She collects each stick individually and carries it, as she flies under her body and looks like she is riding a tiny broom!

Can you tell us more about filming the adders mating? Is this a filming first or a new behaviour captured?

Filming this number of adders mating has never been filmed before; in some of our mating balls we filmed six adders, a behaviour that is exceptionally rare to see, let alone to film. Across the three weeks filming for this sequence, we found at least 52 different individual adders, guided by the expert identification skills of herpetologist Nigel Hand. By closely and carefully following the individuals as they emerged from hibernation, and particularly by following the males which sometimes moved hundreds of metres following the scent of a female, we were able to pinpoint the exact locations where mating was taking place to capture the extraordinary footage of this moment. We had a camera team of three people, and an additional field team of four people, who were all assigned spotting duties to follow individual adders that we expected to mate or battle. Everyone was in radio communication ensuring that as soon as any behaviour looked likely, the nearest member of the camera team could be called in to quickly relocate and film the action.

Interview with Cameraman Alastair MacEwen

Scenes Alastair was involved in filming

• Episode 1: Our Precious Isles – Lords and Ladies & Arum lilies pollination story | banded demoiselles, courtship and egg laying underwater | bumble bee pollination | butterfly meadows
• Episode 2: Woodland – wood ants | ash black slugs | fungi releasing spores | fungi time lapses
• Episode 3: Grassland – bee and snail shells | large blue butterfly | field voles
• Episode 4: Freshwater – raft spider

What was the most interesting macro sequence that you filmed?

Filming the large blue butterfly was the most interesting for many reasons. Its life history and its relationship with the ant is totally fascinating and we felt it had to be recorded to be shared with a television audience. This butterfly went extinct in the UK because of changes to its habitat, a familiar and sad tale of our times. However, the making of Wild Isles has coincided with remarkable conservation success. Through careful scientific management, the butterfly has been brought back and can be seen once more in British meadows, giving us a glimmer of hope for the future. The filming was a challenge in so many ways. It is always necessary to film specific key moments of behaviour to tell any story about animal behaviour – miss just one of them and you have failed. With this project every one of these moments involved behaviour so complex and so sensitive to disturbance that the task frequently seemed beyond reach.

Can you tell us about the kit you needed to film this type of animal behaviour?

We filmed in two different meadows using the sloping terrain and short camera supports to get the lens as low as possible. To show the details of the ant behaviour as clearly as possible, it was necessary to get lenses low enough and into hidden places to see what was happening. It was practically the last minute of the last hour of filming when, finally, we got the last essential moment – when an ant brought the caterpillar into the nest.

Why did you want to be involved in a series about wildlife in the British Isles?

I have been involved in many shoots and one or two programmes made in Britain and Ireland. We have stories here equal to some of the strangest found in the tropics, but our climate is a perennial problem. It’s hard to predict how long field work will take especially if sun is needed for behaviour or beauty. When Wild Isles was planned it seemed a great opportunity to try and do the nature of Britain and Ireland justice.

Can you tell us more about how you filmed the “witch bee” nesting inside old snail shells?

This engaging and entertaining little bee, its broomstick behaviour and its quest for snail shells led us to try and tell its story as fully as possible. We worked closely with a field biologist who could help us find our subjects and knew the timings of the different behaviours we needed to film. To film inside the shell, the first and most obvious thing to do was to film through the front aperture to get shots where the bee or jaws of the bee were visible. I also cut a window in an old shell to allow camera access to the back. The shell was just translucent enough for lighting and I placed it, attached to the front of the scope, in the meadow in a place the bee was looking for shells and camouflaged the scope with grass. By great fortune the bee checked my shell and entered it. At the right time I carefully cut a window in a shell with egg and pollen inside, sealed the window with a coverslip to keep the egg at the right humidity and filmed close-ups of the egg and larva.