Mottistone Down is part of the Butterfly walks book
Green Hairstreak can be found quite readily on the downland
Clouded Yellows are seen every year on the down
Small Coppers can be found on the Eastern part of the slope
Glanville Fritillaries can be found in small numbers.
Seeing Orchids on the down is a highlight
Six Belted Clearwing is a Nationally rare Moth and can be seen where its foodplant Birds Foot Tre-foil on the downland
The Dark Green Fritillary is one of the dominant species to be seen on the downland, flying in late June and July, and at least a dozen or so can be seen flying around and taking nectar from Thistles and Knapweed
The Grayling is not a common butterfly on the chalk, but the Isle of Wight is one of the few places where you can see it.
This area of chalk grassland is undergoing restoration following a period when the site had been heavily scrubbed, and large areas had been planted with trees. An extensive tree removal programme has been undertaken, and much scrub has been cleared. The site is grazed periodically by Highland cattle in order to control scrub invasion. Some scrubby areas have been retained - these are dominated by Gorse Ulex europaeus. Some Blackthorn is also present.
Within parts of the recently cleared areas Ground Ivy Glechoma hederacea is abundant, providing a useful Spring foraging source for bees and other insects. Elsewhere on recently cleared areas Wild Parsnip Pastinaca sativa grows in some quantity. Cowslip Primula veris is infrequent on the site, although small patches occur, particularly in the North - west of the site. Wild Strawberry Fragaria vesca is abundant in places.
Towards the South - eastern end of the site there are large exposures of bare chalk which are the remnants of a disused chalk pit. In the eastern sector of the site there are pockets of chalk grassland with typical calcareous grassland indicator species including Common Rock Rose Helianthemum nummularia, Horseshoe Vetch Hippocrepis comosa, Thyme Thymus polytrichus, Small Scabious Scabiosa columbaria , Musk Thistle Carduus nutans, Dwarf Thistle Cirsium acaule and Harebell Campanula rotundifolia. Common Rock Rose is abundant around SZ40618454 and SZ40538459. Common Bird’s - foot Trefoil Lotus corniculatus is also present.
RARE, SCARCE AND BAP SPECIES RECORDED FROM MOTTISTONE DOWN, LEPIDOPTERA.
The Dark Green Fritillary Argynnis aglaja was recorded on the Down during July and August, although numbers appear to be quite low. Larvae of this species feed on Common Dog Violet Viola riviniana, which is quite widely scattered across the site. This butterfly is classified as Nationally Scarce (N) and in view of a major local decline over the last few decades, the Dark Green Fritillary is included in the Isle of Wight BAP listings. Brook and Compton Downs are the island stronghold for the Dark Green Fritillary on the Island.
As habitat restoration progresses on Mottistone Down, it is likely that numbers of this attractive butterfly will increase. Although not considered Nationally Scarce, the Grayling butterfly Hipparchia semele has undergone a major local and national decline in recent decades, so it was heartening to find this species in reasonable numbers at Mottistone Down in July and August.
The Grayling favours the area around the old chalk pit at the south - east of the site, around SZ405845. Larvae of this butterfly feed on several species of grasses. The grayling is an Isle of wight BAP species. The Nationally Scarce (N) butterfly the Adonis Blue Lysandra bellargus was found to be present in small numbers on the Down, particularly at the eastern end of the site around the chalk pit. Larvae feed on Horseshoe Vetch Hippocrepis comosa, which grows in small quantities around the chalk pit. Although a number of relatively strong colonies occur on chalk downland sites on the Island, the Adonis Blue has declined considerably on a national scale. Although there are signs of a recovery in recent years, the Adonis Blue remains a national BAP priority species.
Small numbers of the Chalkhill Blue Lysandra coridon were found flying on Mottistone Down in August. This is another Nationally Scarce (N) chalk grassland species whose larvae feed on Horseshoe Vetch, and like the Adonis Blue, it has declined considerably on a national scale. Because of the current limited distribution of the foodplant on Mottistone Down, most specimens were seen around the chalk pit at the eastern end of the site. It is considered a national BAP species of conservation concern. Some Island populations of Chalkhill Blue, for example that on Littleton Down, may number several thousand individuals in good years.
Caterpillars of the rare (RDB3) Glanville Fritillary Melitaea cinxia were found At least 10 individuals were seen; they were scattered over some distance suggesting the presence of several webs on the site. Adults were recorded on each visit during June, with a maximum count of 9 individuals. This butterfly is now native only to the Isle of Wight within the UK, and is largely restricted to coastal localities along the South of the Island between Sandown Bay and Compton Bay. Glanville Fritillaries occasionally form inland colonies along the chalk ridge, although these are usually transitory in nature. It is therefore interesting to note that Pope (1999) states that the Mottistone Down colony was present in 1989, and he considered it to be the most stable inland colony for the species. The 6 larvae feed on Ribwort Plantain Plantago lanceolata. In view of it’s highly restricted distribution,the Glanville Fritillary is included in the national BAP listings as a species of conservation concern.
Small numbers of the diurnal Six - belted clearwing moth Bembecia scopigera were observed flying around clumps of Bird’s - foot Trefoil Lotus corniculatus, the larval foodplant of B. scopigera. This plant is thinly distributed within the site, particularly in the more southerly sections of the Down. Adult specimens of the Six - belted clearwing were observed flying rapidly around the flowers of this plant. This nationally scarce (Na) species is found quite regularly along the soft rock cliffs of the Island where L. corniculatus is present, but only occasionally recording it inland on the Island. Nationally it has a scattered distribution through England as far North as Yorkshire. It has also been recorded in Wales.