This was the truly magical sight that awaited me when I arrived at Lavernock Nature Reserve last Tuesday morning.

As I walked the footpaths across the fields, more Marsh fritillaries than I’ve ever seen before were flitting up briefly from their perches before settling back down again in the grass.

I’d heard last Sunday that the first fritillaries of the year had been spotted, which is around 10 days earlier than any previous year. That seems to be the norm with butterflies this year, with our warmer than usual and very dry Spring weather.

These Marsh fritillaries were illegally introduced to Lavernock back in 2022, a practice that seems to be increasing across Britain. Whether they will continue to thrive is unknown but, in the meantime, and despite the manner of their arrival and their unknown provenance, they are certainly a joy to behold.

It’s happening again. Some idiot is fiddling with our local butterflies, illegally. This month, Marsh fritillaries have been spotted at Lavernock Nature Reserve, at Cosmeston Lakes Country Park, and along one of the reens (streams) at Rumney, on the eastern outskirts of Cardiff.

The sightings at Cosmeston and Rumney were of solitary butterflies and, though Cosmeston is not much more than a mile from Lavernock, Rumney is nowhere near any known site and Marsh fritillaries are not strong fliers so neither of these butterflies is likely to have arrived accidently. Also, though Cosmeston does have some areas of Devil’s-bit scabious, the butterfly’s larval food plant, Rumney has none. Hence my description of the person doing this as an idiot – the butterflies at Cosmeston and Rumney have no chance at all of establishing a colony.

The situation at Lavernock is a little different, as at least three Marsh fritillaries were found there last year (see An illegal introduction, May 2022). There is a slim possibility those butterflies bred and this year’s fritillaries are the result, but the experts I’ve been in contact with believe it is much more likely these 2023 butterflies are more illegal introductions.

The British population of Marsh fritillaries has been in steady decline for many years so these gorgeous butterflies definitely need help but these random releases in unsuitable locations are not the answer. In south Wales, a large-scale, properly managed and licensed conservation project is already underway. If you’re interested in finding out more, check out the project page and the more recent news page on the Initiative for Nature Conservation Cymru (INCC) website.