Why we must protect site of some of Britain’s rarest butterflies

We never appreciate the value of some things until they are gone, which is why amateur naturalist ERIC BROWN says it is important to save Hutchinson’s Bank nature reserve from the threat of intrusive development by Croydon Council’s house-building company

The Glanville fritillary is found at only three sites in the United Kingdom – and Hutchinson’s Bank is one of them

From my Kent home, it takes about an hour negotiating the narrow and often choked south London streets until you finally reach the end of the tramlines at New Addington.

Soon after the tramlines disappear, a left turn takes you into a different world. Houses and bustle recede, trees and fields border the road and the ear-chafing sound of trams, buses and lorries is replaced by birdsong.

A mile or two further and I park in a quiet, narrow lane which ends in a footpath. I walk along the tree-tunnel path and at the end emerge into bright sunlight alongside an information board announcing that I have arrived at Hutchinson’s Bank.

No customers visit this bank to withdraw wads of notes or pay their bills. For Hutchinson’s Bank is a 34-acre nature reserve, the largest stretch of chalk grassland surviving on the edge of London. Just four miles south of the bustling town centre of Croydon, it is designated a Site of Metropolitan Importance for Nature, a Local Nature Reserve, A Conservation Site and it is also Green Belt land.

Hutchinson’s Bank, Chapel Bank and Threecorner Grove, all managed by the London Wildlife Trust, represent a rare and precious corner of downland habitat that cannot be replaced

Hutchinson’s Bank and two smaller adjacent reserves – Chapel Bank and Threecorner Grove – adding up to nearly 70 acres in total, have been managed by The London Wildlife Trust since 1986.

Situated on a steep hillside, it looks like someone has sliced through the land with a cake knife to create a spectacular valley.

Buzzards can be heard overhead, as well as the occasional loud roar of the old Merlin engines straining to get a Spitfire airborne from nearby Biggin Hill.

But the quarry most people seek when visiting Hutchinson’s Bank is as silent as a football ground under covid-19 lockdown.

More than 30 species of butterfly have been recorded here: large, small, medium and in a kaleidoscope of colours. Blue, light brown, dark brown, red, yellow, green, white, grey, orange, maybe spotted, veined or striped flying machines, all inhabit grazed slopes during the course of a summer.

The small blue butterfly is one of many species found at Hutchinson’s Bank

The sun beats down, reflecting off the flower-strewn banks to create temperatures comfortably in excess of the official 26C announced on my May visiting day last year.

If only my teachers had concentrated more on flower ID than boring pistils and stamens I might have been able to name more of these flowers. But I’m especially focused on the yellow ones as they are favourites of the butterfly I seek. I come across common blue, dingy skipper, grizzled skipper, several small heaths, brimstone and small blue. There’s green hairstreak but no brown hairstreak, one of the reserve’s specialities.

An exciting, rich variety, but none of these are what I have come here to look for. A lull occurs and as the heat of the sun becomes almost unbearable, I decide to leave. Reaching the exit I mention my disappointment to two other visitors who say they have just seen my quarry on the lower path. Performing an abrupt about-turn, I hurry down some steps and immediately, some distance ahead, I see a couple of brown butterflies pockmarked with black lines on their upper wings and black spots on underwings.

They are whirling around each other in what seems to be a frenzied airborne courtship dance.

Definitely fritillaries and as I get nearer I can see they are what I have been looking for – Glanville fritillaries. One soon flies off but the other settles on the path, permitting close-range photography.

These butterflies are a real British rarity.

On the northern fringe of their range, Hutchinson’s Bank in Croydon and a site in Somerset are the only known bases in mainland Britain to host Glanvilles. Even their main site near Ventnor on the Isle of Wight was devastated recently when a great spotted cuckoo found Granville caterpillars much to its taste.

It is a protected species under the 1981 Wildlife and Countryside Act. Their populations are very fragile. The first time I visited Hutchinson’s Bank there were around nine Glanvilles flying around. The next time, none at all. The third time there were just the two, as described above.

Granvilles are a precious and rare site, even at Hutchinson’s Bank

It was originally called the Dullidge fritillary, as it was found in Dulwich. Then the plantain fritillary, after the foodplant of its caterpillars. And then the Lincolnshire fritillary.

Finally, in the 18th century, it was re-named the Glanville fritillary to commemorate Eleanor Glanville, an eminent butterfly enthusiast whose will was contested by her son on the grounds that any woman studying butterflies could not be of sound mind. He won the case, too.

Yet now development is in the air at Hutchinson’s Bank, with a proposal to build housing right next to the entrance to the reserve.

We cannot allow scarce butterflies like the brown hairstreak and Glanville fritillary to come under threat from the bulldozers.

To volunteer at Hutchinson’s Bank go to volunteering@wildlondon.org.uk

About insidecroydon

News, views and analysis about the people of Croydon, their lives and political times in the diverse and most-populated borough in London. Based in Croydon and edited by Steven Downes. To contact us, please email inside.croydon@btinternet.com
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2 Responses to Why we must protect site of some of Britain’s rarest butterflies

  1. We need to protect the butterflies from its deadliest predator, worse than man alone. It is the fearsome, all-consuming Scottnegrininewmanosaurus.

    Like a virus, it destroys all green spaces and all the species that live on them.

    It is impervious to attacks, reason, logic, kindness, consideration or compassion.

    It has a variety of recondite and not very humanoid skills which allow it to either devour all opposition or to destroy it by making use of any dubious stratagem that lies within or just without the boundaries of law or responsible behaviour.

  2. croydonres says:

    Thank you Eric and Inside Croydon for this incredibly helpful and detailed (and well-illustrated) article, which I hope is read by all Councillors, especially those on the Planning Committee

    Like I suppose “most people” I recognise the need for new development to provide better homes for people who either currently have no home, or a poor quality home. But this is subject to having a vision of what is “The right development in the right place”. I know that this is to a degree, subjective, but it is also a case of balance, as to what is special about a place, and the alternatives, and what local people think as well as decision makers..

    NewAddington is a big place, and there are probably alterrnative, far less sensitive sites for a new block . It seems that many local residents, who know their area, think this. I hope that in view of the concerns being voiced, that the councillors enter into a discussion with the local people, and other people who care about Hutchinson’s Bank, about other possible sites for development, and only after having exhausted other potentials, consider this one.

    Once built, a building like this will not be unbuilt, and will last maybe for 100 years or more. That’s a long time, if a development is in the wrong place.

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