In late-summer Cornwall, Wall Browns feed on peak-bloom Red Clover, their second brood thriving in the warm, flower-rich grasslands that link butterfly and plant in a finely tuned seasonal partnership.
In August, Cornwall’s grasslands carry the colours of late summer—golden tussocks, russet seed heads, and the jewel-like blooms of Red Clover. In this warm and open landscape, the Wall Brown butterfly (Lasiommata megera) is in its second peak of the year, a flicker of orange and brown drifting between sunlit stones and nectar-rich flowers.
The Wall Brown is a medium-sized butterfly, with a wingspan of 44 to 53 millimetres. Its wings are a tapestry of orange and brown, patterned with dark spots and eyespots near the edges. Males bear a dark scent band on the forewing, females are a touch larger and often more vivid in tone.
In Cornwall, they are creatures of open, sun-warmed grassland—especially along the coast. Here, the mild maritime climate, short turf, and patches of bare ground create ideal conditions for basking, one of the butterfly’s most important behaviours. They perch on dry ground, stone paths, or old walls, absorbing warmth that fuels their flight, mating, and foraging.
Wall Browns are double-brooded in most years. The first brood emerges in spring, peaking in May and June, but it is the second brood—late July through August—that often feels most in tune with Cornwall’s late summer.
In warm years, a partial third brood can appear, but in Cornwall this is occasional and often incomplete, with some adults emerging too late to find enough nectar or suitable conditions to produce a viable next generation. Coastal sites give these butterflies a longer active day than inland meadows, allowing them to feed earlier and later in the sunlight and take full advantage of August’s nectar.
Red Clover (Trifolium pratense) thrives in Cornwall from May into October, but August is its moment of abundance. In unimproved meadows, roadside verges, and dry pasture, it blooms thickly, its pinkish-red flower heads offering a concentrated source of nectar.
For the Wall Brown, Red Clover is a favourite among several late-summer nectar plants—others include knapweed, scabious, and thistles. The second brood emerges just as these flowers are at their most generous, creating near-perfect synchrony between butterfly and plant. Feeding bouts on clover and its companions sustain the energy needed for mating flights and egg-laying, ensuring the next generation begins before summer fades.
While adults rely on flowers for nectar, the caterpillars feed exclusively on grasses—most often Cock’s-foot, Yorkshire Fog, and various Bents in Cornwall’s coastal grasslands. Tor-grass, common in inland limestone areas elsewhere in Britain, is less frequent here. Larvae graze mainly at night, resting motionless along grass blades by day, camouflaged within the turf.
These grasses often grow alongside wildflowers like Red Clover, creating an interconnected habitat where nectar and larval food plants coexist. Healthy, species-rich meadows maintain this balance, but both clover and caterpillar grasses suffer where grasslands are overgrazed, ploughed, or replaced by improved pasture.
Several behaviours help the Wall Brown thrive in Cornwall’s August grasslands:
These adaptations, combined with the region’s mild coastal microclimates, make Cornwall a stronghold for the species—even as inland UK populations have declined sharply since the 1970s due to habitat change and climate stress. Coastal numbers remain more stable, though they can fluctuate from year to year.
Cornwall’s wildflower succession—from spring’s thrift and bird’s-foot trefoil to summer knapweed, scabious, and clover—extends the Wall Brown’s feeding window across multiple broods. In August, Red Clover takes centre stage, blooming alongside sheep’s-bit scabious and greater knapweed.
In very dry summers, even coastal meadows can develop a nectar gap in late August unless grazing and cutting are carefully timed. This management is vital to ensure continuous nectar for late broods and other pollinators.
Climate change is altering the timing of both butterfly emergence and wildflower blooms. Warmer springs can bring earlier flowering, raising the risk of “phenological mismatches,” where butterflies reach peak activity after key nectar plants have already faded.
Longer warm seasons might allow for extra broods, but these can be vulnerable to sudden autumn weather changes or lack of nectar late in the year. Drier conditions may also shift meadow plant communities toward drought-tolerant species, sometimes reducing nectar diversity.
In Cornwall, coastal grasslands still offer refuge—warm, flower-rich, and diverse—but habitat fragmentation, drought, and changes in land management could challenge this delicate balance. Conservation work to maintain unimproved grassland, create wildlife corridors, and stagger mowing regimes will be vital.
A late-summer meadow in Cornwall holds a quiet vibrancy. The grass crunches underfoot, clover blooms cluster like tiny garnets, and the Wall Brown moves with a measured rhythm—settling to bask, rising to feed, circling in search of a mate. Here, plant and butterfly are bound by season and place, each marking the high point of summer before the slow turn toward autumn.
Best Time to Look
Where to Search
Recognising the Habitat
Look for:
Identifying the Butterfly
Behaviour to Watch
Conservation Note
If you find a good Wall Brown site, avoid trampling or picking flowers. These butterflies rely on the combined presence of nectar-rich wildflowers and caterpillar food grasses—disturbance during peak bloom can reduce resources for the next generation.
