Painted Lady

The Big Butterfly Count

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Butterfly Conservation’s Big Butterfly Count starts today, a chance to get involved counting these beautiful insects and contribute to an important citizen science project. The count runs for a few weeks at the end of July and beginning of August each year and provides a wealth of data. Not only does it tell conservationists how butterflies are faring, but also how healthy our environment is as a whole.

The Importance of Butterflies

Understanding how our butterflies are doing is important for a number of reasons. For starters, along with their fellow pollinators, they are crucial for fertilising a large proportion of crops and flowering plants. By carrying pollen from plant to plant as they seek out nectar, they enable plants to produce seeds and ultimately the next generation. This means they are extremely valuable environmentally and economically.

Big Butterfly Count marbled white
Marbled white is just one of the butterfly species to look out for

Butterflies are also an important part of many creatures’ diets, especially during the caterpillar stage of their lifecycle. Other insects, spiders, toads, frogs, birds and small mammals are just some of the animals that eat them.

Big butterfly count orange tips
Only male orange tips have orange on the wing

One of the central reasons for the annual count, though, is because butterflies are useful indicator species for the health of the environment. Because they react quickly to any changes, they are the proverbial canary in the coalmine, telling scientists when things are not as they should be. By recording and interpreting changes in butterfly populations over time, researchers can see where there are problems and where to concentrate conservation measures.

Butterfly Ups and Downs

Since 1976, a coalition of organisations has been running the United Kingdom Butterfly Monitoring Scheme (UKBMS). This long-running project uses a combination of survey techniques, including transect walking and timed counts, to get a picture of butterfly numbers in the UK. Along with the information from 11 years of Big Butterfly Counts, that picture isn’t a good one. Over 70% of our butterfly species have declined in occurrence over the last 40 years. The losses aren’t restricted to those species with specialist habitat requirements either. Some of those species that conservationists class as habitat generalists, such as wall and small heath, have also declined.

The wall’s decline is not fully understood

There have been some recent success stories, however. The large blue became extinct in the UK in the 1970s. A reintroduction programme began in 1984 and the species has now returned to areas it was absent from for over 150 years. Key to the success of the reintroductions was the discovery that the large blue is completely reliant on a particular species of red ant to raise its young. The butterflies’ larvae are essentially cuckoos in the ants’ nests. The ants in turn have exacting needs when it comes to habitat, preferring grass of a particular length. Conservationists have used livestock to graze reintroduction sites to carefully manage grass lengths and provide ideal conditions for both ants and butterflies.

The chequered skipper butterfly has also been reintroduced to England at a site in Northamptonshire. The species became extinct in England in 1976 and was only hanging on in western Scotland. Following releases of Belgian butterflies in 2018 and 2019 numbers have grown, and the hope is that this species of woodland edges and bracken will spread.

Taking Part in the Big Butterfly Count

Taking part in the Big Butterfly Count couldn’t be easier. All you need to do is find a spot to sit for 15 minutes and count butterflies. Ideally, pick a bright and sunny day as this is when they are most active. You can do more than one count over the three-week period and at more than one location. You just need to enter them into the website as separate counts. It is also important to record if you so no butterflies at all. This information is just as useful as it can show where there have been declines.

Holly Blue
Holly blue
Large white
Large white

To reduce the risk of miscounting species, Butterfly Conservation is only looking for counts of certain target species. There are 17 butterflies and 3 day-flying moths to look out for. Most are fairly widespread and there is also a handy ID chart on the website to help you work out what you have seen. The species they are looking for include brimstone, peacock, gatekeeper, small tortoiseshell butterflies and silver y and six-spot burnet moths.

Red admiral
Red admiral
Big butterfly count common blue female
Common blue female

If you do see a species that isn’t on the target list, you can download the iRecord Butterflies app and add your sighting. You can also use it to keep recording butterflies once this year’s count is over. You will be providing valuable information as the data goes to the national monitoring scheme. There is also a handy list of the species you are likely to see flying in your area at a given time, as well as a guide to all of the UK’s butterfly species. So there is no excuse not to keep counting, whenever you see a butterfly!

Scotch Argus
Scotch Argus is on the Scottish list of butterflies to look for during the count

Further Reading

Bloomsbury’s pocket butterfly guide is a great ID guide to all of the UK’s species. Illustrations are by the brilliant wildlife artist Richard Lewington, who specialises in invertebrates

Naturalist Matthew Oates has spent 50 years watching butterflies, his great passion. In this book he lets us into his world and shares his experiences of a life marvelling at these insects.

Patrick Barkham’s brilliant The Butterfly Isles, on the other hand, recounts just one year spent attempting to see all of the UK’s species, some easier to find than others.

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