Common Blue

Map of the Down

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See also...

Report of the visit from Cambridge Natural History Society in August 2017

News about a visit by the local branch of Butterfly Conservation charity taking place in August 2016

News about the very special area of Colin's Bank, published in February 2015

Butterflies of Magog Down

In 1994 – five years after the farmland that is now Magog Down was purchased by The Magog Trust – it was written that:  As the flora of the Down becomes consolidated and is enhanced by new planting, it is to be hoped that a good butterfly population will establish itself by natural means, that is, as resident species which are common in the Cambridge area spread into it.”  Specific species were thought likely to appear sooner or later – see this table of the relative expectations:

1994: Butterfly expectations for newly created Magog Down

Hoped to establish

Small Tortoiseshell



Red Admiral

Painted Lady


Peacock butterfly



Likely to see

Large White

Small White

Green-veined White

Likely to move in

Meadow Brown

Hedge Brown (or Gatekeeper)

Small Heath


Should appear soon

Large Skipper

Small Skipper

Essex Skipper

Expect to see soon

Common Blue

Small Copper


Could see

Clouded Yellow

May need to artificially introduce

Chalkhill Blue

Small Blue

Marbled White

More about the expectations in 1994 can be read in this archived article.

Professor Colin Smith was the first to carry out regular surveys of the butterfly population (see panel, right). Survey work was done again between 2008 and 2012 by Doug and Jenny Taylor, using  the formal “Transect Method”: a common method for monitoring, where the same area of land is walked regularly, at a constant pace, counting what’s seen within a 5m visual square. Then in 2015 a Friend of Magog Down called Barbara Massingham-Stubbs took up the challenge to resurrect the Butterfly Transects that Doug and Jenny had started. Details about the methodology used are in this news article.

Results of the surveys show that by far the most common butterfly seen now is the Meadow Brown (shown in the table above, second one down), making up just over half of the individuals counted. Others seen in large numbers are the Essex or Small Skipper (bottom image in the table above), the Small White, and the Common Blue. 

marbledwhite_238Comparing Barbara's 2015 and 2016 data, one noticeable increase so far is in numbers of Marbled White (left) and Large Skipper (below).


A grand total of 1605 butterflies from 22 different species were recorded in 2016. We look forward to seeing the results of Barbara's ongoing monitoring in 2017 and beyond.


Big Butterfly Count: 14 July to 6 August 2017

Magog Down is a great place to spot butterflies as part of this nationwide survey. Two of our Governors were meeting another person in the first week of the count, and their list of "spots" is shown below. butterfly_ticked_chart_250

Painted Lady
Common Blue
Hummingbird Hawk moth
Dusky Sallow moth
Six-spot Burnet moth
Small Heath moth
Meadow Brown

Do enjoy your own spotting exercises, and we're always interested to hear about your visits.

Colin's Bank on Magog Down

Professor Colin Smith was a keen lepidopterist who took a great interest in the Down. He was convinced that the increase in the natural flora would provide the necessary food supply to encourage a further growth in the number of Butterfly and Moth species on the Down.

He regularly contributed articles to the Trust's Newsletter and carried out surveys over several years, and by the end of 1995 had recorded 20 species of Butterflies and 152 of Moths.

His death in 1997 is marked by a seat on the North Down, but two years later this site was identified by Dr Max Walters and Gerry Haggett, a Norfolk Naturalist, as one which if cleared of trees and shrubs, would produce an ideal sunny, sheltered bank on which to improve the variety of native chalkland flora. The initial work was carried out in 2000 with financial support from Colin s family.

Further work to improve the diversity of the natural flora providing an increased food supply for Butterflies, Moths and other insects took place in 2004 and was part funded by an Environmental Grant from Cambridge City Council.

Mating butterflies

Numbers may be declining overall but here are two species that were caught in the act! commonblues_mating_250The Common Blue and the Copper have both been spotted mating by Barbara Massingham-Stubbs on her butterfly monitoring - she looks forward to counting their progeny in future years.copper_mating_250