Answers to all your butterfly related questions, along with ideas how to help.

Butterflies are one of our most loved insects, being bright, colourful and associated with summertime. Many species are common in our gardens, but others live in woodland, heaths, coastal areas. All specialising in lifestyle along with habitat.

All butterflies and moths are insects from the order Lepidoptera, which appropriately comes from the Greek words meaning ‘scale’ and ‘wing’. All the colourful patterns on butterfly wings are made up of tiny, coloured scales.
There are in excess of 150,000 identified species of butterflies and moths, 18,000 species of butterfly and the earliest records date back to 40-50-million years ago.
We have 59 recorded species of butterfly in the UK, of which 15 can commonly be seen in gardens.

Why am I not seeing any butterflies in the UK?

The UK has a temperate climate, but conditions can vary widely from year to year. Depending on the weather throughout the four seasons, butterflies may flourish or suffer. A cold winter can kill off hibernating adults and larvae equally. While a cold wet summer can delay or prevent breeding. There are many potential reasons why you might be seeing fewer butterflies in the UK and we explore the min factors below:

1. Prolonged wet weather. Heavy rain can physically dislodge caterpillars from their host plants, making them vulnerable to predators such birds and other insects.
2. Temperature and humidity. Wet conditions can lead to cooler temperatures and increased humidity. This can trigger pathogens such as fungal, bacterial, and viral infections to proliferate. While some caterpillar species might benefit from the added moisture, others may become infected and killed.
3. Food Availability. Climate change increases the chance of extreme weather that can disrupt the life cycles of butterflies. Host plant species that caterpillars feed on, may also be disrupted, reducing their food sources and potentially leading to starvation.
4. Habitat loss. Modern farming techniques, along with urbanisation of our countryside often involve the removal of hedgerows, meadows, and wildflowers (weeds). Reducing availability of habitat, host food plants for growing caterpillars, and nectar rich flowers for adults.
5. Pesticides, and pesticide run-off. Pesticides are indiscriminate and kill butterfly and moth caterpillars and adults! Increased use of pesticides affects butterflies directly and indirectly. Accidental poisoning is common using systemic pesticides in plants that then flowers passing on and kill butterflies sipping contaminated nectar. Additionally, rainfall can lead of pesticide ‘run-off’, from agriculture and gardens into hedgerows and suchlike, indirectly exposing them to lethal chemicals.
6. Invasive Species: Global trade and travel has introduced countless non-native plants, animals and pathogens that can disrupt local ecosystems and outcompete, prey upon, or infect butterflies.

Top 10 Butterfly Facts UK

Where do butterflies go in the summer?

Summer is the time butterflies are at their busiest. Long days, warmer weather trigger adults to breed. During early summer, overwintering butterfly adults will emerge to start feeding on early flowering plants. While overwintering larvae will begin emerging as adult winged butterflies. At the peak of summer adult butterflies will be flying, feeding and mating. While eggs will be laid and caterpillars emerging and feeding. Cocoons will also form and ne adults emerge as some species may have multiple generations in a single season.

1. Where to normally see butterflies in summer?

With 59 resident species and up to 30 visitors migrating, butterflies can be seen throughout the UK. Our gardens play host to 15 or more species, while other species specialise in woodland, heaths, even costal areas.

2. Does the heat impact butterfly populations?

Butterflies are cold blooded insects and need heat to thrive. They become active when temperatures rise above 20°C and tolerate high temperatures well. Cold wet summers can have devasting consequences for both adult and larval butterflies.

Why do butterflies shake?

3. Why do butterfly cocoons shake?

Butterfly cocoons are defenceless against predation. They cannot fly or crawl to safety, so as a defence mechanism they shake violently for a minute or two to frighten off potential dangers. The shaking is triggered when they feel vibrations close by.

4. Why do butterflies shake their wings?

Being cold-blooded butterflies need a body temperature above 20°C to fly. Different species have developed tactics to raise their internal temperature. These include dark wings to capture as much sunlight as possible. Locating micro-niches where warm pockets of air form and commonly, flexing and shaking their wings. This muscle movement heats up their bodies just as we do when we exercise.

5. Why do butterflies shake in their chrysalis?

This is a defence mechanism chrysalis have developed to save them from predation. At the first sign of vibrations, chrysalises will start vibrating and shaking violently to scare off any potential predator.

How to tell if a butterfly is hibernating?

6. Do butterflies hibernate?

Several common butterflies hibernate in the UK. Species such as small tortoiseshell, brimstone, comma and peacock all hibernate as adults and frequently choose garden sheds and garages as cool dry locations to over winter. More species, however, chose to overwinter in immature states larval or pupa states.

7. How to look after a hibernating butterfly?

Technically adult butterflies don’t hibernate but rather go into a state of torpor. During winter the weather is too cold for them to fly and food is in short supply, so they become dormant, sleeping until the weather warms once more.
If they make their way into our houses, once the heating is turned on they may become active even in winter. If you find a sleeping or active butterfly in winter, you should place it in a carboard box and take it to a cool location. Once it’s settled in half an hour or so, the box should be moved to a cold, dry location, such as unheated shed or garage, away from windows, or direct sunlight. Then in spring, the box can be opened on a warm sunny day to wake the butterfly.

8. What does a hibernating butterfly look like?

Hibernating butterflies tend to position themselves in nooks and crevices, in dry areas such as garage and shed roof spaces between timbers. They may also occupy similar crags in trees, and custom-built butterfly houses. They fold their wings together behind their bodies and appear quite dull. Their bodies close to the perch and wings together erect like a sail.

9. Can a butterfly hibernate in the house?

Butterflies often inadvertently find ways into our houses, as cool dry spaces in which to hibernate. They go to sleep in the autumn and enter a state of torpor. However, as e enter winter and switch on our heating systems, the warmth frequently wakes the butterflies, who think it’s springs arrival. They will need relocating to a cold dry place and encouraged to go back to sleep.

10. Are butterfly populations decreasing in the UK?

Alarmingly, over 80% of the UK native butterfly population has been lost since the 1970’s. Decreases in butterfly populations is a national concern. Several species have already been declared extinct in the UK, while half of the remaining species have been put on the red extinction risk register.

What is the Big Butterfly Count?

The Big Butterfly Count is the world’s largest butterfly survey, undertaken by volunteers and gardeners across the UK. Run by Butterfly Conservation, it lasts for just over two weeks from the end of July to the first week of August and involves picking a spot and spending 15 minutes counting the butterflies and moths you can see.

The data gathered is crucial for butterfly scientists wanting to learn more about the population and habits of various butterflies. It enable butterfly experts to assess where conservation efforts are most important.

The data collected during each annual Big Butterfly Count provides valuable insight into the effects of climate change and extreme weather on butterfly habits and population. This citizen science project tracks trends and how we might be able to better protect our beautiful butterflies.

As well as being lots of fun, the information can be gathered by people of all ages, makes a valuable contribution to science and is becoming more valuable as long-term climate change disrupts traditional weather patterns.