A Summer of Butterflies

At Lackford we have recorded 24 different species of butterfly on the reserve this year, and up to 16 of these can be seen by visitors on a good day- the best weather been warm, still and sunny! Among the highlights have been silver-washed fritillary, white admiral, purple hairstreak, painted lady and brown argus but the full list can be found at the bottom of this blog. We've also included the dates they were first spotted here this year- interestingly, the earliest was a peacock on February 24th and the most recent a white admiral on July 28th!

Last year we recorded the first silver-washed fritillary at Lackford and this year we have had at least a couple of individuals on site- we figured this must be the case when two of our volunteers spotted them almost simultaneously- with one specimen looking very tired and ragged while the other much brighter and pretty freshly emerged! They have a particular fondness for bramble and thistle flowers, especially when growing in a wooded setting- sunny clearings in the path next to the Sailing Lake and through Ash Carr might offer the best hope of seeing one. The males of this species roam very widely and can move some distance from where they hatched- ours may have come from as far as Bradfield Woods where there is a burgeoning population of them, whereas the females tend to stay closer to home, feeding and searching for the foliage of common dog violet which they lay their eggs upon.

silver-washed fritillary

Purple hairstreaks probably occupy the highest elevations of any butterfly at Lackford, and can therefore be tricky to see- they spend their days flitting about amongst oak leaves close to the very tops of the trees. They can be very hard to spot in between these short flights but look for a lilac-brown underside, about the size of that of a common blue, resting on a horizontal leaf. When basking with their wings held flat they are much harder to see because of how high up they are! 2017 is the first time they have been seen at Lackford but because they live a discreet life high in the treetops, they may have been here for many years.

purple hairstreak

Another species at its peak on the reserve at the moment is brown argus. It has two broods a year and Church Walk on a sunny day is currently full of individuals from the second brood, which have originated as eggs laid by the first brood in late may and early june. The usual foodplant is common rock rose, but I had never noticed this growing in any quantity at Lackford and wondered what they might be using instead- it turns out the foliage of dove's-foot cranesbill seems to be an adequate substitute after I saw a female egg-laying on some last week! Females lay eggs singly on the underside of suitable leaves, and when the caterpillars hatch they feed only on the underside of the leaf- leaving the top layer of the leaves' cells untouched, creating conspicuous transparent 'windows' on the surface of the leaf which are a tell-tale sign the plant has had brown argus caterpillars munching through it!

brown argus

Another special butterfly- the painted lady- arrived first with us this year on May 31st. We get these butterflies in variable numbers each year, depending on, believe it or not, the abundance of thistles all the way over in the Middle East! Thistles are a painted ladies' favourite foodplant, and where the butterflies reside year round in the Middle East, north Africa and southern Europe, sometimes the population builds to a point where there is a thistle shortage, and something has to give. Mass migrations are triggered, where hordes of butterflies fly north until they find more thistle-filled habitat, and they may travel as far north as Scandinavia in their search. A certain number this spring set up home at Lackford and we are now seeing some lovely fresh individuals on site, who have hatched locally, and whose parents undertook their mammoth journey earlier in the year.

painted lady

Red admirals undertake a similar journey, and both species are very closely related. They are both strong fliers and any adults left at the end of summer undertake a partial migration back to Europe, in search of warmer climes for whatever remains of their lives. In contrast, the brown argus mentioned earlier rarely move more than a few hundred metres from where they emerged- quite a difference! Recent observations suggest that although traditionally red admirals find our climate too cold and damp to survive a winter as a hibernating adult, a warmer climate in recent years may be making it possible for a few individuals to hibernate successfully on the mild south coast of England. Suspicion arose when some very fresh red admirals were emerging on warm spring days, without enough time for them to have travelled up from continental Europe.

red admiral

Now is an excellent time to head down to Lackford to look for butterflies as it's currently peak season. It's a good idea to have a pair of binoculars handy to observe them when they're a little further away. Binoculars are also great for looking at the finer details of individuals closer to you.

By Heidi Jones (volunteer at Lackford Lakes)