Photo above top right by Trevor Baker

All other photos including header photo by Martin Partridge

The Speckled Wood is a medium-sized chocolate brown butterfly with pale yellow or cream blotches, single small eyespots on upper forewings, and three or four pupilled spots towards the lower edges of its upper hindwings.  Female are slightly larger than males and have stronger markings though if a single butterfly is seen it can be hard to tell if it is a male or female.

Overwintered pupae produce butterflies with larger, paler, yellow patches than overwintered larvae, although the latter are usually bigger in size.  The second and third broods tend to be darker than the first spring brood.

Males are very territorial and often perch on low branches in sunny parts of dappled shade habitats such as the edge of woods and often fly up and inspect any passing humans.

The Speckled Wood is usually found in woodland clearings and on the edge of woods, or roadsides with high hedges.  It can also be found in gardens, parks and any area where around half of the light is excluded.  Having said that the butterfly does like basking in sunshine with its wings flat open in.

It lays its eggs on a wide range of grasses, including grasses in sand dunes and on wetland heaths such as Thorne moors.  The species has colonised farm tracks, lanes and disused railway tracks where even short lengths of high hedge provide some shade and it is often to be found where there are brambles which the adults nectar on.  It also loves scrubby, semi-wooded paths, where the males patrol up and down.

The Speckled Wood is now well distributed throughout Yorkshire and succeeding very well in rapidly expanding its range.

The species was more common and widespread in Yorkshire in the mid 19th century but crashed in late 19th century.  Re-expansion began in the 1920s, reached Yorkshire in 1940s and continues north at a fast pace.  This is probably due to global warming, with the recent expansion largely proceeding along the north-south orientated Magnesian Limestone ridge in Yorkshire.

For some years the Speckled Wood did better in the south and then later in the north west of England as well, perhaps because it was damper and possibly warmer in the north west compared to the north east and larvae continue to develop in winter when temperatures are above 6°C.  However the species is now well re-established across most of the north, and it’s possible that range expanding individuals are now mixing with older, more established populations in the Highlands of Scotland for the first time in over 100 years.

Outside Britain the species is common and widespread from northern Africa to Norway and across Asia to the Urals.

There are two or three overlapping broods between April and October with peaks usually May and June, July to August then September to October.  In the northern Dales this butterfly is often the first one seen in spring and the last one seen in autumn.

The life cycle is complex and unusual for a butterfly, it being capable of overwintering as either a larva or a pupa.

Pale eggs are laid singly on the underside of many species of grass blades, especially False Brome Brachypodium sylvaticum, Cock's-foot Dactylis glomerata, Yorkshire Fog Holcus lanatus and Common Couch Elytrigia repens.  The female chooses sunny areas in spring and autumn, but shadier sites in summer.

Development is very sensitive to temperature and may vary from site to site.  The yellow-striped green larvae continue feeding on and off through winter whenever the temperature rises above 6°C and pupal stages vary from as little as 10 days in summer to several months through winter.  The mid- to late-summer in Yorkshire often has two distinct peaks resulting from different growth speeds of overwintered larvae and pupae.  Cool weather in June can effectively separate these two peaks by inhibiting the emergence of the second spring flight and extending its period into early July.  This also has the effect of producing a later than usual peak emergence in August onwards.  A partial third brood may occur in October.

A proportion of males, often those with four upper hindwing spots, are territorial, perching on sunlit vegetation about one metre from the ground and watching for passing females and defending against patrolling males.  Other males, often the 3-spotted variety, and especially those from the summer brood, patrol through their breeding areas searching for females.  Females spend much time high in the canopy of trees except when egg laying.  Males and females also feed high up on honeydew, although if this is unavailable they will nectar on flowers and also feed on fruit.

The species is not under threat.

The species is quite variable with over 30 described aberrations.  Rarely the pale yellow spotting may be replaced by a dull orange (ab intermediana Lempke), or be paler (ab pallida Tutt).  In Britain there are two subspecies; subspecies tircis (Godart 1821) is in the south of England plus up as far north as Yorkshire and Cumbria, and subspecies oblita (Harrison 1949) is in Scotland.  In addition there is the the insula subspecies, which thrives on the Scilly Isles.  It has bigger spots and is very bright.

With thanks to The Butterflies of Yorkshire edited by Howard M Frost  and Dr Andy Suggitt