Downs Chalkhill Blue and Adder
Adder (Vipera berus)
Vipera berus is the common European adder, with distinctive V patterning and which can be found throughout most of Western Europe. Whilst quite rarely seen, they can sometimes be spotted basking on South Downs hillsides or under warm rocks in the summer.
The common adder is found in different terrains, habitat complexity being essential for different aspects of its behaviour. It feeds on small mammals, birds, lizards, amphibians and in some cases on spiders, worms and insects. Females breed once every two or three years with litters usually born in late summer to early autumn. The common adder is ovoviviparous, meaning they lay eggs with litters range in size from 3 to 20, with the young snakes staying with their mothers for a few days. Adults grow to a length of 60 to 90 cm (24 to 35 in) and a weight of 50g (1.8 oz) to about 180g (6.3 oz).
It is safe to watch one from a few metres away as, whilst they are venomous and bites can be painful, they are not aggressive and usually bite only when alarmed or disturbed.
Chalkhill Blue (Polyommatus coridon)
The Chalkhill Blue is a butterfly in the family Lycaenidae and is usually seen on the wing for about 6-8 weeks during July to September. This pair of Chalk-Hill Blue butterflies is seen mating on a naturalist's hand. Great care was taken with these butterflies and the pair climbed onto the hand shown in the video briefly before being returned to the location close nearby where they were originally found.
Males have pale silvery-blue wings with black and white border. Females are dark brown, also with the black and white borders. The Chalkhill blue favours unimproved (and unfertilised) chalk downland such as is found on the South Downs. Its larval caterpillar foodplant is Horseshoe Vetch (Hippocrepis comosa).