This month sees the start of Butterfly Conservation’s annual Big Butterfly Count. The organisation is asking people to record their butterfly and day-flying moth sightings from July 20 to the end of August.

All you have to do is count the species and numbers of butterflies you see in a 15-minute period, preferably on a bright and sunny day. You can do this as many times and wherever you like.

Records are welcome from gardens, parks, woodlands, school grounds, allotments and the general countryside. All the details are available at http://www.bigbutterflycount.org.

This is the fourth year of what has become the biggest butterfly survey in the world, butterflies being an ideal subject for this type of project. They are widespread in urban and rural areas, easily spotted, and many species are distinctive enough for most people to make an accurate identification.

They are also good indicators of general environmental quality, responding quickly to changes both good and bad. The survey is described by Butterfly Conservation as ‘Taking the pulse of nature’.

Last year, over 27,000 people took part in the survey. The numbers of many species were well down because of the wet weather, and this year there may well be a knock-on effect from that.

Longer term declines would be an early warning that other species may be in trouble. Familiar butterflies whose numbers were reduced include holly blue, all three common whites, speckled wood and red admiral.

Peacock butterflies suffered a massive 89 per cent decline compared to 2011.

There was some good news. Amongst the browns, meadow brown (the most recorded species), ringlet and marbled white showed spectacular increases. These may be linked to the lush growth of the grasses upon which they feed, ironically because of the very wet weather, and slightly better conditions during their main flight period. In the Black Country the slopes of the Rowley Hills have become a stronghold for marbled whites.

We may never again see clouds of butterflies fluttering over flower-filled meadows, but your gardens and allotments can help to fill the gap. It is important that we understand how well insects are doing in these habitats, and the survey is one of the tools to help us do this.

* Peter Shirley is a nature conservationist with interests from neighbourhood to global ecological issues