We recently enjoyed a presentation entitled Butterflies of The New Forest by Jacky Adams and Nigel Owen, both active members of Butterfly Conservation. The life cycle of butterflies comprises four stages: egg, caterpillar or larva, chrysalis or pupa and adult butterfly. The caterpillar stage is when the serious eating happens and they change their skins as they grow larger; the nectaring by the adult serves only to keep it alive during its’ flight period. How long is spent in each stage varies from species to species - for example the Green Hairstreak spends 9 - 10 months as a pupa; the Pearl-bordered Fritillary spends 10 months as a caterpillar. The phase in which each species over winters varies: many do so as caterpillars, finding a secluded and safe spot. The speckled wood can over winter either as a caterpillar or as a chrysalis. Five of our resident species over winter as adult butterflies, Red Admiral, Comma, Peacock, and Small Tortoiseshell (our favourite garden butterflies) and the Brimstone, which could be regarded as the harbinger of spring. These adult butterflies, when they emerge in spring do of course create the first generation of the new year. The Small Tortoiseshell has been suffering a serious decline in numbers for some years and a staggering 32% drop in sightings this year. The caterpillar of the comma once ate hops exclusively but with this in increasingly short supply had the good sense to start eating nettles like the others in this group (save for the Brimstone) and reversed a serious decline some year ago.
In Britain there are about 59 resident and regular migrant species many occurring in the New Forest. Getting to see them will depend upon the correct habitat, the time of emergence and, importantly, good weather, preferably warm sunshine. Sometimes the rarer the butterfly is the shorter the flight period, examples being Pearl-bordered Fritillary and Duke of Burgundy. In contrast, the Speckled Wood is available throughout the summer with successive broods and it will also fly in conditions that other butterflies dislike. In addition to the “garden species” mentioned above the whites may also be found in ones’ garden. These are the not so popular Large and Small White (the scientific name of the Large White is Pieris brassicae!) the Green-veined White and the Orange Tip. The caterpillars of the latter two do not eat cabbages but cruciferous plants.
The New Forest has its’ share of the rarer butterflies. There are a few colonies of Pearl-bordered Fritillary, formerly a common species in coppiced woodland. The beautiful White Admiral with its’ floating flight can be found in some areas of shady woodland. Clouded Yellows arrive here in varying numbers and can sometimes be seen particularly on the coast or downland. There are reports of them overwintering infrequently. In contrast the migrant Painted Lady cannot survive winter temperatures whatever stage has been reached in the breeding cycle; this butterfly very occasionally arrives here in tremendous numbers. The Glanville Fritillary’s stronghold is on the Isle of Wight though attempts to establish itself here on the coastal mainland have been short-lived only.
The speakers concluded by describing how we can all help encourage butterflies in the garden by growing nectar producing flowers and allowing some nettles and long grass to grow. Also to participate in the annual Big Butterfly Count and consider joining the New Forest Transect Group to carry out counts on a regular basis. AB