Of all our butterflies, one group immediately springs to mind when we think of hot summer days. On a south-facing downland slope, bright blue butterflies skip and chase across the hillside.

It’s on grasslands like St Catherine’s Hill Nature Reserve in Winchester that the blues really come into their own. The familiar common blue, the large powder-blue chalkhill blue and the dazzling Adonis blue butterfly can be seen on the wing together, and in the best years on the best sites, the numbers can be staggering.

However these stunning butterflies have been in decline, with some halving in numbers in as little as two decades. Not only does this threaten our food production - one out of every three mouthfuls of food that we eat depends on pollination taking place - but it also impacts upon other species, like the farmland birds that feed on these insects.

One of the main causes for the decline in butterflies, bees and other pollinators in the UK is the way that landscapes have been managed over the last 50 years. 97% of wildflower meadows have disappeared and pesticides have been introduced, making it increasing difficult for them to find the food and shelter that they need.

There are many things that we as individuals can do to help, from planting nectar-rich flowers to providing homes such as bug hotels. But what we really need to do now is to work in a bigger, joined-up way to ensure that these wonderful and essential species can thrive.

Find out more about what you can do to protect pollinators at: www.hiwwt.org.uk/take-action-wildlife/wildlife-gardening

Identifying blue butterflies:

Common Blue: the common blue is a small butterfly which flies throughout the summer between April and October. The most widespread of the blue butterflies, it is found in a variety of habitats including heathland, woodland rides, grassy meadows, parks and even large gardens.

Chalkhill Blue: this butterfly is found on the chalk grasslands of southern England. The males are the more conspicuous as they fly searching for the secretive females. The males are silvery blue with a dark brown/black border and a white fringe on the wings. The females are brown with a white fringe to the wings and a blue dusting near the body. They are one of the largest blue butterflies found in Britain.

Adonis Blue: the Adonis blue is one of the rarest of the blue butterflies in the UK. It is found on sunny, south-facing grassland rich in herbs. Adonis blue larvae have a symbiotic relationship with ants, which provide protection from predation in return for sweet secretions from the larvae’s ‘honey glands’.