Please read in conjunction with other related butterfly blog posts and photographs of British butterflies on this website:
When I was a kid my world was smaller and simpler than it is today. I was frustrated that not all of the 59 different species of British butterflies were visiting my garden. I didn't have a car to go exploring, but I did have a bike, so I would scour the country lanes in the search for new species that I hadn't seen in our garden. And, when we went on holidays with our parents, it was always an exciting opportunity to explore new territory and find different butterflies. I remember seeing my first marbled white on the grassy and sunny banks of the Severn Estuary at Clevedon, during a family trip to the coast for a picnic.
As a kid, I did however quickly come to understand that different butterfly species had different habitat requirements, and in particular, that they need to lay their eggs on a specific type of plant suited to their fussing-eating caterpillars to feed on when they hatch. I therefore started to grow common host plants, such as stinging nettles in the garden, in the hope that regular visitors to the garden, like the Small Tortoiseshell and Peacock butterflies, would lay their eggs on them, just like they did just on the big patch nettles growing outside our house by the side of the road. Even to this day, decades later, I have never seen a single egg on the nettles in our garden. Ironically though, as soon as I grew a few cabbages in the garden, the cabbage white butterflies were laying their eggs all over them!
So what determines which butterflies visit your garden and how can you influence them? Well its mainly a combination of four key factors; the type of plants you have growing in your garden, the types of habitats in your neighbourhood, the combination of the geographic spread of each speicies and their mobility. The first one is in your control - you can grow plants that attract butterflies, the second you can influence, by engaging in local discussions, processes and activities, that determine how the land and habitats in your neighbourhood are managed, and even what plants are grown. And the third and fourth, well, there's not that much you can do to change the inherent characteristics of butterflies, but by understanding the relative mobility and the geographic spread of the different species of UK butterflies, you can better understand which ones you should be able to attract, which ones you can influence, and which ones you can't!
1. Plants & Habitats in your Garden
Gardens provide essential habitat for butterflies and a much-needed source of food through flowers for butterflies and plants for caterpillars. The main way British gardens attract butterflies is by providing nectar-producing flowering plants that are easy for butterflies to extract the sugar rich nectar from. Not all flowers have adapted to be pollinated by butterflies so its important to choose carefully. There are many texts available online suggesting nectar sources for butterflies, including for UK species. Buddleia, commonly known as the butterfly bush, is perhaps the single most important source of nectar for butterflies in the UK, due to its prolific flowering heads that butterflies flock to, and its ease of growing. In our garden, known at IFABW as 'Reserve 21', I refer to the buddleia bushes as butterfly catchers, as they seem to reach up and pluck butterflies straight out of the sky.
As well as planting nectar-producing flowers, letting an area of your garden grow wild, and allowing the grasses to grow tall, could attract a range of regular visitors to your garden – including the Meadow Brown, Speckled Wood, Gatekeeper, Small Skipper, Marbled White and Ringlet. The more these wild plants meet the exacting egg laying requirements of butterflies, the more visitors you're likely to have. Lists of host plants for the caterpillars of each species of British butterfly can easily be found online. Unfortunetaly many of our caterpillar host plants, like nettles, are considered weeds by gardeners and not tolerated at all, or are cut down in their prime before the eggs have had chance to hatch at all. Some species require specialised habitats, such as chalk downland or coppiced woodland which are generally not found in most gardens so you're unlikely to be see these species in gardens.
2. Plants & Habitats in your Neighbourhood
During the last few hundred years, the way we manage the landscape in Britain has changed dramatically. The advancement of mechanisation, the opening up of the British agricultural economy to global competition, the post war drive for domestic food security, and the widespread use of fertilisers and chemicals to control weeds and pests have all resulted in the complete loss, or the severe degradation, of habitats and biodiversity, and with it, a massive decline in the quantities of butterflies in the UK.
The drive to maximise the landscape for agricultural productivity lead to removal of thousands of miles of biodiverse rich hedgreows, and the almost total loss of wildflower rich meadows in favour of pastures with 'improved' grass species, were devastating for UK butterflies. Traditional rural industries, such as coppicing and reed cutting, more or less disappeared due to cheaper imports or the development of less sustainable alternatives, and with them the unique landscapes that were created by these gentle forms of land management disappeared, and with them the specific species of butterflies that were able to thrive in these man made ecological niches. Even the natural elements of our villages and towns are harshly managed with herbicides and aggressive cutting of hedgerows and road verges with little thought given to the various stages of the butterfly lifecycle that tries to utilise these slithers of wilderness.
It's important to realise that most of our butterflies are adapted to very specific habitats and even the felling of a single tree can result in the complete loss of a colony of butterflies. Purple Hairstreaks, for example, set-up colonies in a single oak tree, and can rely on it exclusively for generations and generations. Fell that tree and the colony has gone forever, unless it's felled when adults are on the wing and have the chance to relocate to another oak tree and enough time also to lay eggs to ensure another generation.
The type of habitats in your neighbourhood and surrounding countryside and how they are managed, especially in terms of both nectar sources and host plants, have therefore, a massive impact on the quantity and diversity of butterfly species that may stray from these areas and visit your garden looking for supplementary nectar sources in particular. It is important to join forces with similarly minded people and engage with local authorities, to form groups, to volunteer and even start your own initiative. In my local area concerned people formed a group called 'Friends of Westerleigh Common' and campaigned for this somewhat unloved and under used public open space to be saved and didn't stop there. The common has now undergone partial re-wilding which some decades later is a beautiful wildlife rich area enjoyed by many and which acts as an important pesticide free reservoir for butterfly species for the whole area.
3. Geographic Spread
Geographic spread is linked to the availability of suitable ecological conditions and even niches such as those exploited by the Swallowtail and Large Blue butterflies for example. The British Swallowtail, that lives in a very specific type of agricultural wetland landscape, is a subspecies of its continental cousin that lives in similar habitats in Europe. Major changes in the management of these 'fen' lands resulted in the almost extinction of the subspecies as it failed to find another source of its host plant, the scarce wetland milk parsley plant, in another niche. Therefore it maybe highly mobile and a strong flier but it wasn't capable of expanding its geographic spread due its dependence on a single species of plant.
Geographic spread can be interpreted in several ways, how far it flies versus how far it has naturalised. For example the highly mobile Painted Lady is a migrant to the UK from Africa, but it has not adapted to the cold British winters, and therefore doesn't overwinter in the UK. Remarkably, all those Painted Ladies that we see in large number all over the country during the summer, are part of a massive process of bulking-up the population before returning to Africa in bigger numbers than when they arrived in! The Red Admiral which is another highly mobile migrant from Africa, also seen in large numbers in the UK each summer, has in recent years however, managed to overwinter in the UK and therefore expanded its geographic spread in terms of naturalisation. It doesn't however make the return journey to Africa unlike its cousin (they are both members of the Nymphalidae family).
The excellent website UK Butterflies, has a searchable map of the distribution / density of species across Britain and Ireland. It clearly shows that the highest density of different species occurs in the central south of England, probably due to having longer day lengths and warmer temperatures, combined with less industrialisation and quite a mix of different types of landscapes. Its proximity to the warmer parts of continental Europe just across the English Channel may also be an important factor, especially given the similarity of most British butterflies to species in Europe.
4. Mobility
In terms of mobility, the more mobile the butterfly species, the more likely it's to visit our gardens. There are three main categories of butterflies based on mobility:
- Migrant Species that are Strong Flying and Highly Mobile
The most mobile species are those that undertake true migrations that follow well defined flight paths year-after-year, including the incredible Painted Lady and Red Admiral whose epic migrations I will celebrate in a separate post soon! These highly mobile butterflies are often seen in our gardens, some may stay for a few days to feed on the abundant nectar of buddleia for instance, before resuming their migration north. Provided you have good nectar sources in your garden there is a good chance you will see them in your garden, and if there are nettles, hops and thistles, then there is a possibility that Red Admirals and Painted Ladies may lay eggs in your garden that will hatch during that same summer.
- Non-Migrant Species that are Strong Flying and Highly Mobile
The next most mobile, are the non-migrant species that breed in locations where all the habitat requirements are met for egg-laying but whose adults are strong fliers and travel long distances to feed and seek mates. The Holly Blue, Brimstone and Orange Tip are such species and all wander through the countryside. If your garden is well-stocked with suitable nectar plants then there is every chance that some of these species will visit your garden. Furthermore if you also have some plants in your garden that are suitable for emerging caterpillars to feed on, then there is a chance that some of the species that use these plants as host plants will lay some eggs on them. It is also possible, if you're garden is large enough, and has areas of host plants that are stable from year to year, that some species might set up territories and stay for years to come.
- Non-Migrant Species with Low Mobility and which Live in Distinct Colonies
The least mobile butterflies, which make up the majority of British butterfly species, are very localised and live in sedentary colonies, such as the Adonis Blue and Pearl-Bordered Fritillary. Such species don't go far from their home territories, but occasionally, some may stray into your garden looking for additional nectar sources. However unless your garden has all the exacting habitat features that the colony requires then it's highly unlikely they will ever breed or lay eggs in your garden. These local populations do however make the range of species that visit your garden much more interesting given the proportion of British species they represent, and it's therefore important to maintain the quality of the local natural habitat, not only where they have their colonies, but also between your garden and the colonies, if you want them to thrive and continue to visit your garden.
So if you can't attract and you can't influence butterflies then what can you do? Well the obvious answer is, if they can't come to you, then go to them. It was only until relatively recently that I have started to make special excursions to target specific species of butterfly realising that this was the only way I was ever realistically going to see many of the British species. This involves not only identifying where these species have colonies, but also at what time of the year they are on the wing. For example, I travelled to a specific site in Somerset to spot the elusive Purple Hairstreak, which is a small butterfly with a brilliant purple sheen, that is found in oak woodland and which flies between the end of June and early September. Now there are oak trees and some oak woodlands near me but I have never seen any Purple Hairstreaks there so I went to a group of trees, known in the local butterfly world, to have some colonies and without fail I spotted them high up in the tops of the oak trees.
In the case of the very rare Large Blue, it wasn't just a case that I wasn't looking hard enough for them my local grassland habitats. The Large Blue was, until recently, extinct in the whole of the UK due mainly to a change in the way its habitats were managed. The Large Blue is particularly vulnerable because of its very unusual lifecycle that requires a unique combination of different plants and other insect species to complete its lifecycle, but I will save the details for another day. The Large Blue was successfully re-introduced to the Daneway Banks Nature Reserve in Gloucestershire. The Reserve is perfect for a wide range of butterflies, due to its sunny aspect and its limestone grassland habitat that is known for its floristic richness (there can be over 40 species of wildflower per square metre of grassland) which is in full bloom at Daneway during the spring and summer. A sunny June or July day is the perfect time to spot butterflies there, and on my trip, I was thrilled to see the Large Blue as well as the Dark Green Fritillary, Marbled White and Small Blue.
I also visited Lower Woods, which like Daneway Banks, is a nature reserve run by the Gloucestershire Wildlife Trust, to see the magnificent Silver-Washed Fritillary, and I wasn't disappointed - it is perhaps the most exotic looking butterfly I have ever seen in the UK.
Wildlife Trusts actually, provide an important role in preserving important butterfly habitats and enabling access to them by the general public. This is very important, as the vast majority of land in the UK, is both privately owned, and therefore inaccessible to the general public, but also this land is predominately used for intensive agriculture, which therefore has minimal habitat suitable for wildlife, apart from the field margins and hedgerows, which are important reservoirs and corridors, in what is sadly, a very wildlife depleted landscape. This is a topic I hope to cover in more detail soon.
Finally, I am hoping soon to travel to the other side of the country to see the UK's largest, and one of its rarest, butterflies, the Swallowtail, which is confined to the wet fenlands of the Norfolk Broads in East Norfolk. As with many other butterfly species, its fate lies largely on the way our natural landscapes are managed and that is also a topic for another blog! But don't expect to see one in your garden anytime soon!
References
https://www.wildlifetrusts.org...
https://www.somersetwildlife.o...
https://www.broads-authority.g...
https://wildlifeworld.co.uk/pa...
https://www.countryfile.com/wi...
https://www.ukbutterflies.co.uk/nectar_sources.php
https://www.ukbutterflies.co.uk/foodplants.php