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My first encounter with the rare large heath butterfly

Large heath butterfly on Winmarleigh Moss - Credit: A.J.Critch Wildlife

Summer is finally here and so are the butterflies. Their return means it’s time for the Lancashire Wildlife Trust peatlands team to head out and survey the rare large heath butterfly on our peatland reserves.

Since starting at the Lancashire Wildlife Trust as the Peatlands Communications Officer, I have written about this butterfly, spoken about this butterfly, seen lots and lots of photos of this butterfly, and even hosted a drawing workshop which featured this butterfly, but never once have I seen this butterfly. So, when the surveying season arrived, I was eager to get out to try and spot the large heath butterfly.

The peatlands team survey two of the Trusts peatland reserves; Winmarleigh Moss SSSI in Lancashire and Astley Moss SSSI in Greater Manchester. Winmarleigh is a stronghold for this butterfly, the population managing to hang on even whilst the bog was previously drained and damaged.

The first large heath butterfly to emerge at Astley Moss when being reintroduced to the peatland reserve.

The first large heath butterfly to emerge during the 2020 reintroduction project at Astley Moss - Credit: Andy Osborne

It was this surviving population that was then able to act as the donors for a reintroduction programme back in 2020, where we brought the locally named 'Manchester argus' back to Astley Moss, where they had been missing from the area for approximately 100 years.

My surveying experience at Winmarleigh Moss

Upon arriving at Winmarleigh Moss, you are welcomed by a carpet of multi-coloured sphagnum moss, making every footstep soggy and spongey. Among the sphagnum moss was bog cranberry, bog myrtle, fluffy cotton grasses and my favourite, round-leaved sundews.

A landscape photo of Winmarleigh Moss during large heath butterfly surveying.

Winmarleigh Moss - Credit: Lancashire Wildlife Trust

In the first survey area, I immediately spotted the large heath butterfly. I had been waiting for this moment and there it finally was. Within moments another fluttered by, and another. I didn’t know how many to expect, I wasn’t sure I’d even see one.

I continued to spot more large heath as we ventured onward but was tricked a few times by the latticed heath, a similar looking butterfly but noticeably smaller in size. The sightings were less frequent as we headed into other areas of the reserve. However, this did not mean there was any less wildlife there. Lapwings were now in sight, but it wasn’t just lapwing I could see as a redshank quickly took to the sky to warn us to stay away, which we did.

Two separate photos of a lapwing on the ground and a redshank in flight.

Lapwing - Credit: A.J.Critch Wildlife (left) | Redshank - Credit: Peter Cairns 2020/VISION (right)

Because this next area of the moss we visited wasn’t as far along its restoration journey as our starting point, the large heath butterfly sightings had come to a stop. Not enough caterpillar food plants and fewer nectar supplying plants such as cross leaved heath meant a population of large heath wouldn’t be able to live in this section. My eyes were now drawn to the other interesting residents of Winmarleigh.

Hare’s tail cotton grass was on full display, the fluffy seed heads blowing in the wind. Getting up close to the round-leaved sundews, I could see flies that had been caught in their sticky droplets, in the process of being devoured by these carnivorous plants.

Fluffy cotton grass on a boggy Winmarleigh Moss

Fluffy cotton grass on a boggy Winmarleigh Moss - Credit: A.J.Critch Wildlife

A round-leaved sundew catching a fly.

Round-leaved sundew - Credit: A.J.Critch Wildlife

A dark red sphagnum capillifolium on Winmarleigh Moss.

Sphagnum capillifolium on Winmarleigh Moss - Credit: Lancashire Wildlife Trust

Three flies caught in a round-leaved sundew.

Three flies caught on a round-leaved sundew - Credit: A.J.Critch Wildlife

Cotton grass on Winmarleigh Moss

Cotton grass on Winmarleigh Moss - Credit: A.J.Critch Wildlife 

Lots of small bird footprints in the bare peat at Winmarleigh Moss.

Bird footprints in the bare peat at Winmarleigh Moss - Credit: Lancashire Wildlife Trust

Large heath butterfly on Winmarleigh Moss.

Large heath butterfly on Winmarleigh Moss - Credit: A.J.Critch Wildlife

Just as we were heading back, I caught sight of one more large heath butterfly. It was a surprise to see one in this area of the moss, but a happy surprise indeed. This was a clear indication that the population was doing well and venturing further afield. This butterfly took a minute to rest on some heather, just long enough for me to get a photo.

Whilst walking back more birds were spotted. I saw my first stonechat perched on a fence post, a reed bunting flickering between the reed beds, and I even heard a meadow pipit flying high in the sky along with oystercatchers and swifts. Overall, it was a very successful day spotting some of Lancashire’s finest wildlife.

Seeing my first large heath butterfly is one of my favourite wildlife encounters to date. However, the sad reality is that this butterfly was once a common sight across our region. This shouldn’t be such a special encounter, it should be a regular one, one which will only be made possible by protecting and restoring our peatland habitats.

If you want to learn more about the reintroduction of the large heath butterfly, read the article below.

How do you reintroduce an extinct butterfly?

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