Wall Brown

The Wall Brown, also known just simply as the Wall, has fluctuated in abundance within Britain and Ireland over the last hundred or so years. Today it is quite scarce across large parts of southern, central and eastern England. The bright markings of this species more closely resemble those of the fritillaries than the more familiar browns like Gatekeeper, Meadow Brown and Speckled Wood.

Behaviour and Ecology

Males spend a lot of their time either basking on the ground or actively patrolling their territories. The females also a lot of time basking or visiting flowers, though they are less conspicuous when laying their eggs. These are deposited singly on the leaf blades of grasses like cock’s-foot, yorkshire fog and wavy hair grass. The eggs hatch after about ten days and the resulting first brood caterpillars pupate into adults after about seven weeks (five as a caterpillar and two as a chrysalis). Those caterpillars that make up the second brood, overwinter in this form, and so spend about six months as a caterpillar, only pupating in the April or May of the following year.

The basking behaviour enables the butterfly to raise its body temperature to some 8-10C above its surroundings, an important characteristic because they need to reach a body temperature of 25-30C to fly. In windy weather, their body temperature can fall quite quickly so individuals then have to bask again. On very hot days, individuals face the problem of overheating and may even move into the shade to regulate their temperature.

Identification

Although superficially similar in appearance to the various fritillaries, the bright eyespots are usually obvious enough to secure identification. Males have a line of scent scales (known as the ‘sex-brand’ and a feature sported by some other species) and this appears as an oblique dark line across the upper surface of the forewing. Females lack this feature and are both larger and brighter in colour than their mates. Both sexes display some beautifully subtle markings on their underwings, which provide very effective camouflage when at rest. Basking individuals often angle their open wings towards the sun.

Wall Brown (upperside)		Wall Brown (underside)		Wall Brown (caterpillar)
				photograph to be added

The use of gardens - results from Garden BirdWatch

Although not evident from the garden reporting rate graph (see below), the Wall normally produces two broods each year, the first is on the wing from late April until late June and the second on the wing from mid-July through to mid-September. In hot summers, a third brood may sometimes fly in late September and October.

Seasonality in the use made of Garden BirdWatch gardens by Wall Browns during 2003

The favoured habitats of this species include the short-turf of rabbit-grazed downland, coastal dunes and disused railway lines. As such, this species only infrequently appears in gardens, hence the low reporting rates in the following graphs.

Differences in the use of rural, suburban and urban gardens during 2003

Although absent from many areas of southern, central and eastern England (as well as most of Scotland and large swathes of Ireland, this species seems to do well in coastal areas. It is here that the local climate may be more favourable, especially since this species loves to back on broken, sun-baked ground. Click here to see a map showing the distribution of Wall Browns within gardens at the national level, as recorded by BTO/CJ Garden BirdWatchers during 2003.

Regional variation in the use of gardens by Wall Browns during 2003

Click here to see what the region codes on the above graph mean.

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Page last updated 3 September, 2004

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