UK Butterflies

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Small Heath

Coenonympha pamphilus

SEE-no-nymph-uh PAM-fi-luss

Wingspan
♂ 33 mm, ♀ 37 mm

Checklist Number
59.005

Small Heath

Coenonympha pamphilus

SEE-no-nymph-uh PAM-fi-luss

Wingspan
♂ 33 mm, ♀ 37 mm

Checklist Number
59.005


Despite its name, the Small Heath is not confined to heathland and can be found in a wide variety of habitats. The main distinguishing feature of this species is that this is the smallest of our 'browns' and is closer in size to a skipper, Common Blue or Brown Argus than its relatives, such as the Meadow Brown. However, its fluttering flight is quite different from that of the skippers and blues and is relatively-easy to identify in the field. This charming little butterfly always settles with its wings closed, where the eye spot on the underside of the forewing is usually visible, acting as a decoy to any predator. The forewings are tucked behind the hindwings when roosting for long periods, or in dull weather, the butterfly looking quite inconspicuous as the browns and greys of the underside of the hindwing blend in with their surroundings.

This is a widespread butterfly and can be found over most of the British Isles, with the exception of Orkney and Shetland and mountainous regions. It lives in discrete colonies and adults rarely venture far from the colony. However, the odd adult will venture further afield and will colonise nearby habitat if it is suitable.

This species was first defined in Linnaeus (1758) as shown here (type locality: Europe).

The nominate form is found throughout the range of this species, with the exception of some area of the Hebrides in north-west Scotland, as discussed under ssp. rhoumensis.

This subspecies was first defined in Harrison (1948) as shown here (type locality: Isle of Rhum, Scotland).

This subspecies is found on the Isle of Rhum in the North Ebudes of Scotland, where it is widespread and common. Harrison (1951) extends its distribution to North Uist, South Uist, Eriskay and "one or two of the smaller members of" the Barra isles (but not Barra itself) and Harrison (1952) further extends this to Raasay where he also says "It is perhaps worthy of note that on Rhum the butterfly flew at an elevation of over 1,000 ft. on Barkeval and at 1,500 ft. on Ruinsival, whilst it occurred at sea level, with Argynnis selene and its congener C.tullia, along the northern shores of Loch Scresort".

Wiltshire (1967) questions the validity of a separate subtaxon based on specimens in the Rothschild-Cockayne-Kettlewell collection, taken in the Hebrides, which conformed to the nominate form. This subspecies differs from the nominate subspecies as follows:

  • 1. Forewing underside has a duller ground colour and a narrower pale area around the eye spot.
  • 2. Hindwing underside largely grey rather than brown. The white band is inconspicuous, narrower and often absent.

Coenonympha pamphilus ssp. rhoumensis (Harrison, 1948)

Forewings: on the underside with a duller brown ground colour and with the pale area around the ocellus narrower than in northern English specimens of the species.

Hindwings: on the underside English examples have the ground broken into three areas, a basal brownish portion tending to chestnut, a conspicuous yellowish-white median band, often quite broad, and a terminal or marginal band in which are to be seen the obsolescent brownish ocelli. In race rhoumensis the basal section is more or less grey sprinkled, its vestiture of greyish hairs preventing its ever appearing of a brown hue, whilst the inconspicuous median hand, reduced in width and often obsolescent, especially toward the inner margin, is also of a greyer colour merging into that of the grey terminal band. Ocelli also greyer than in English specimens.

On the whole, race rhoumensis tends to agree in the uniformity of its underside colouration with the race scotica, Stgr., of the allied species C. tullia.

Holotype ♂, allotype ♀ and 5 paratype ♂♂, Isle of Rhum, 9th-12th June; collected by J.W.H.H. and being deposited in the Hope Department, University Museum, Oxford.

Description to be completed.

The distribution data (2000-2009) has been made available through the generosity of Butterfly Conservation and any subspecies distribution is taken from Riley (2007). Click here to see the distribution of this species together with site information overlaid.

This species can be found in many different habitats, especially those that are more open, such as grassland, heathland, railway embankments, disused quarries, meadows and sand dunes. It occurs only sparingly in woodland where it can be found in ones and twos along wide woodland rides. Wherever it occurs, the adults prefer a shorter grass sward than closely related species.

This butterfly has shown a severe decline over the long term and is therefore a priority species for conservation efforts.

The table below shows the occurrence (distribution) and abundance (population) trends, using information from The State of the UK's Butterflies 2015 (Fox, 2015). Any UK BAP status is taken from the UK Biodiversity Action Plan (UK BAP) (2007 review).

UK BAP Status
Occurrence Change
1976-2014 (%)
Abundance Change
1976-2014 (%)
Occurrence Change
2005-2014 (%)
Abundance Change
2005-2014 (%)
Priority Species
Click here to access the Biodiversity Action Plan (BAP).
Large Decrease -57Large Decrease -54Stable -7Increase +18

Populations found in the north have one generation each year, while populations in the south have two generations each year and possibly three in exceptional years. Adults can be found continuously from late May until mid-September as a result. In all locations, it is the larva that overwinters.

"This species is on the wing from May till October. The first brood appears in May, June and July, and a partial second brood occurs in August and September. Eggs laid in May and June produce the autumn butterflies, as part of the larva feed up and pupate within about twelve weeks after the eggs are deposited, while the remaining larva hibernate and produce imagines the following May. Eggs laid in July also produce butterflies in May, and eggs laid in the autumn hatch in about two weeks' time and the larvae feed until the cold weather; they then hibernate, which results in the later examples of the first brood. The winter months are passed in the larval state, generally after the third moult, which usually takes place about the end of September, and hibernation commences in October; but the larvae do not go through complete torpidity, as they feed in mild weather during the winter." - Frohawk (1924)

Coenonympha pamphilus ssp. pamphilus

Coenonympha pamphilus ssp. rhoumensis

Males set up territories where they can be found perching, although they also spend time patrolling in search of a mate. When a male encounters another, the pair flies a few metres up into the air before separating. Virgin females will also zig-zag over the vegetation in search of a mate. Mating may happen at any time of day and a mating pair may remain coupled from as little as 10 minutes up to 5 hours.

Mated females tend to avoid male territories, flying over sparse grassland where they lay their eggs. Both sexes feed on a variety of nectar sources.

Adults feed primarily on brambles (Rubus spp.), buttercups (Ranunculus spp.), Common Fleabane (Pulicaria dysenterica), Devil's-bit Scabious (Succisa pratensis), Greater Stitchwort (Stellaria holostea), Kidney Vetch (Anthyllis vulneraria), ragworts (Jacobaea spp.), Tormentil (Potentilla erecta) and Yarrow (Achillea millefolium).

The almost-spherical eggs are laid singly on a grass blade or nearby vegetation. They are pale green when first laid, eventually turning straw-coloured and covered in blotches. This stage lasts around 2 weeks.

"Eggs deposited on May 21st, 1890, hatched on June 8th, the egg state lasting sixteen days. Eggs laid on July 16th, 1894, hatched on July 30th, being fourteen days in the egg stage. Eggs laid on July 18th, 1900, hatched on July 30th, remaining twelve days in the egg stage, the whole period being very warm weather. The normal duration of the egg stage is about fourteen days. The egg is very large for the size of the butterfly, being 0.70 mm. high and rather less in width. It is of a truncated oblong shape, the sides convex, but mostly so nearest the base, which is slightly rounded; the crown is sunken, but with a raised convex centre; the whole surface of the apex is pitted, somewhat resembling the punctures of a thimble; there are about fifty longitudinal keels of irregular formation, mostly running from the apical brim to the base; the spaces between are very faintly ribbed transversely. When first laid the colour is a clear light green, gradually changing to a more ochreous-green with irregular blotches of light sienna-brown. Some specimens are distinctly zoned. The colour change is continuous, gradually becoming lighter ochreous and afterwards a very pale creamy-buff, banded with purplish-grey, and finally to a transparent white glass-like shell through which the larva is most clearly visible." - Frohawk (1924)

Larvae spend most of their time tucked away at the base of a tuft of grass, feeding at night on the tender tips of grass blades. Depending on conditions, larvae will either go on to produce adults in the same year, or may overwinter.

The primary larval foodplants are bents (Agrostis spp.), fescues (Festuca spp.) and meadow-grasses (Poa spp.).

1st Instar

"Directly after emergence the larva is 1.7 mm. long; the body is cylindrical and tapering. The head is large, globular and ochreous-yellow with dark eye-spots and a few very short club-like hairs, and has a granulated surface. The body has likewise a fine granular surface, the segments are divided into six sub-divisions forming transverse wrinkles, the first is double the width of the others, all of which are of equal thickness; there is a medio-dorsal and a sub-dorsal longitudinal stripe, of a burnt-sienna or pale rust colour, and below the latter stripe is a much paler and rather narrower one; a broader ochreous spiracular band; on the side of each segment are three claw-like hooks placed in a triangle, one close to the medio-dorsal stripe in the centre of the first sub-division, the second on the fourth wrinkle just above the sub-dorsal stripe, the third above the spiracle. The lateral ridge is composed of a series of bulbous lobes overhanging the base of the claspers, three on each segment; on the first, which is very large, are two short, club-shaped, white, glassy hairs, and a third one on the next lobe, forming a lateral series; the claspers have two spine-like, sharp, simple hairs directed downwards. The anal points terminate in a peculiar club-shaped appendage; the claspers and legs are pale ochreous-yellow; the ground colour of the body is cream, with a whitish lateral band. Before first moult it measures 3.5 mm. long. The colouring is pale green with the longitudinal lines of an olive-green, and a white lateral line; the head is rather more olive-ochreous than when first hatched. They feed principally at night, remaining low down among the grass stems during day, and when disturbed they curve both ends of the body upwards, forming a crescent, and hold to the grass only by the middle claspers." - Frohawk (1924)

2nd Instar

"First moult August 5th, 1900. After first moult, seven days old, it is 5.4 mm. long. The colouring is similar to that before moulting, but the head is now green like the body, which is much more densely studded with the minute claw-like hooks, and the white lateral line is rather more conspicuous. They are very sluggish in their movements, and upon any disturbance readily fall to the ground, and remain for a short time in a crescentic form, but the reverse way to when they are holding on the grass." - Frohawk (1924)

3rd Instar

"Some of the larva moulted the second time at the end of August and others during the first few days of September. After the second moult, thirty-two days old, it measures 6.3 mm. long. The colouring is more clearly defined and rather brighter than in the previous stage and both head and body are still more densely studded with tiny curved spines, each rising from a white bulbous base, thereby giving the whole surface a rough appearance; every wrinkle of the body bears about twenty spines above the spiracular line, whereas in the first stage there are only six on each segment, therefore in the present stage each segment has about 120; in all about 1,440 are distributed over the whole upper surface of the body. They feed chiefly at night and rest on the edge of the grass blades during the day." - Frohawk (1924)

4th Instar

"At the end of September the larvae moult the third time, and after feeding for a time, i.e., as long as the weather remains mild, they hibernate when the first cold sets in. During hibernation, when the temperature is sufficiently warm at daytime, they crawl up the grass blades to feed, and when finished return to their resting places at the base of the grass stalks, where they rest in a straight position, but on being disturbed they fall to the ground. While hibernating on January 17th, 1901, when 170 days old, it measures 8.5 mm. in length. It is similar in all respects to the last stage, except that the anal points now show a pink tinge. When 250 days old, before fourth moult, on April 4th, it measures 11 mm. long; the colour is now more clearly defined, with a ground colour of a pale whitish-green, a medio-dorsal longitudinal dark green line and a rather paler sub-dorsal one bordered below by a fine whitish-yellow line, then a lateral green band divided down the centre by a fine light line; the brownish spiracles are situated on the lower half of the band, the sub-spiracular line is well defined, of a greenish-white colour; the legs, claspers and anal points are tinged with brownish-pink. The whole of the ventral surface is a clear green. The head is paler green, sprinkled with whitish warts, each with a minute spine similar to those on the body." - Frohawk (1924)

5th Instar

"Fourth and last moult, April 16th, 1901. After fourth moult, fully grown, about 270 days old, it measures while crawling 19 mm. long, and 16 mm. while resting; the head is larger than the first segment, the body increasing in size to the fourth segment and gradually tapering to the anal segment, which terminates in two points; these are pink and white and furnished with short white spines. The ground colour of the upper half of the body is pale yellowish-green and the lower half dark green. There are medio-dorsal and sub-dorsal dark green longitudinal stripes, the former is broader and darker; both are bordered on each side by a whitish-green line; a broad spiracular band of dull ochreous-green, which is divided down the centre by a very fine pale line, on which are the ochreous spiracles with brown rims; bordering this band is a light greenish-lemon-yellow lateral line extending from the first to last segments; the whole of the ventral surface is dark green; the legs and claspers have a lilac tinge; the head is clear green. The whole surface of the body, including the head, is sprinkled with minute white warts, each having a tiny short curved spine, some dark and some light; those on the claspers are straight; the surface is also granulated and over the ventral half very minute black specks are densely sprinkled. After hibernation the larva very frequently feed during the daytime. The first one spun up for pupation early morning, April 28th. It attached itself by the anal claspers to a pad of silk spun on a grass blade, hanging in the form of a hook with its head resting against the claspers of the eighth segment. It pupated at 4 p.m. on May 2nd, 1901, being four and a half days undergoing the transformation." - Frohawk (1924)

The pupa is formed, head down, attached to a plant stem by the cremaster. This stage lasts around 3 weeks.

"The pupa is 8.5 mm. long, stout in proportion to the length. The head is truncated, the thorax slightly keeled and swollen dorsally; abdomen rounded and swollen in the middle and curved to the anal segment, which terminates in a projecting point, somewhat flattened and square when viewed dorsally; it is furnished with an ample supply of cremastral hooks, which are singularly long, and ending in a perfectly formed crook of a rich amber colour. The wings are full and swollen. The inner margin of the wing is slightly projecting, forming a longitudinal ridge, which is rather conspicuously streaked with drab-brown and white; two other brownish streaks run parallel to the nervures, one about the middle and the other near the apex; the apical half of the proboscis is purplish-dark-brown; a sub-dorsal series of yellowish-white warts extends along the abdomen, one pair on each segment. The colouring at first is a brilliant light green with abdominal segments pale yellow-green, showing the dorsal and sub-dorsal lines of the larva indistinctly. When four days old, in full colour, it is whitish-green finely irrorated with darker green, giving the general impression of a brilliant clear green; along the abdomen is a longitudinal medio-dorsal band of darker green, which becomes narrower and darker on the thorax; the cremaster is pinkish-ochreous with a dark brown lateral bar. It is suspended by the cremastral hooks, which are firmly anchored to the ample pad of silk spun on the grass blade or stalk. The pupa described began to change colour on May 24th and gradually deepened in colouring, and the imago (a female) emerged on May 28th, 1901, the pupal stage occupying twenty-six days." - Frohawk (1924)