Recording and monitoring carried out by volunteers is vital for the conservation of butterflies and moths.

- Butterfly Conservation Trust

If you've been out on some of our Community Woodlands or green spaces this year - particularly on warm, sunny days - it's possible you might have seen some of our team out and about with net in hand and a keen eye on the grass verges alongside our pathways...

That's because since April we've been busy regularly walking routes at Shocott Spring, Folly Wood, Ridgeway Wood (in Gateway Woods), Rectory Wood, The Grange Estate and Millennium Country Park on the hunt for butterflies! 

After an unfortunate false start in 2020 due to Covid restrictions, our Senior Ranger Nicola was able to see months of planning become a reality as our volunteer butterfly survey team got out on site to start recording species present in the grasses and verges along our woodland pathways.

As well as heading up our recording efforts she was also in charge of training our willing Volunteers, mapping the transects and monitoring the surveys progress - she also wrote this great piece earlier in the year about how climate change can impact our butterfly population, and what we can do to try and help.

For the 26 weeks between April and September either Nicola or one of our volunteers would visit each site and walk a Butterfly Transect - a walk along a set route, divided into separate sections - each week, observing the butterfly species within the 2 metre vicinity of the pathway.

Each time a species was spotted it was recorded in a tally on our species list, so that we could build up a good picture of not only what was seen but also how many were in this particular transect area. When the conditions were right and there were plenty of butterflies to spot it was sometimes difficult to observe and record all at once, which is why our volunteers often walked their routes in pairs - one person kept a keen eye, and one was ready with the pencil and recording sheet!

Although we knew that some of the common species would dominate our results, we expected each site would have slightly different results because of the differences in habitat and other known wildlife nearby. To build up a complete picture of variable conditions on the day it was important to record climactic conditions too, as that could have an affect on the results - time of day, average temperature, average windspeed and percentage of sunlight were all noted on our recording sheets. The perfect day to record would be from late morning until around 5pm, on a dry, bright and still day with a warm (but not hot) temperature - unfortunately we didn't get too many of those...!

Once finished our surveyors would record species, frequency and conditions on a centralised spreadsheet for Nicola to oversee. With this being our pilot year we used this exercise to test and perfect our systems, and hope that next year we will be able to report our findings to the local records centre for inclusion in wider species monitoring programmes.

Our results...

Despite willingness from our surveyors to get out and recording, unusually wet, windy or dull conditions over the spring and summer months made it difficult sometimes.

Sadly we think this did impact our results, as recorded numbers were lower than we would have expected at all sites. However we did still have some really exciting finds and notable results...

This dingy skipper (photo: Alan Garner) was spotted at Millennium Country Park, by Volunteer Butterfly Surveyor Alan at the start of May. We also had dingy skipper spotted on one of our Butterfly Transects at Shocott Spring, which was an exciting find as we did not know that the species was at this site. Dingy skipper is a UK Biodiversity Action Plan (BAP) priority species and a species of principal concern under the Natural Environment Research Council (NERC) act. We usually get these on our callow mounds, and they are one of the target species for our transects. They like ex-quarry and brownfield sites and their food plant is birds-foot-treffoil which we have lots of in that particular area of the site. They are usually on the wing from the end of April to mid-June, so be sure to keep your eyes peeled next year.

The silver wash fritillary butterfly is a species usually associated with ancient woodland, so we were delighted when one was spotted on a visit to Rectory Wood - we think that it must have flown over from neighbouring Marston Thrift that runs adjacent to our Community Woodland. This large, fast-flying butterfly can be spotted in sunny glades and rides in broadleaf woodland during the height of the summer months, but actually breeds in the shadier parts deeper in the woodland – we hope that as our woodland at Cranfield matures it might support a wider distribution. Numbers of this species were in decline during the 1990s-2000s, but have made a better showing in recent decades and appear to be spreading more widely so we hope to see them on site again!

If you're interested in learning more about the butterflies in your local area then be sure to check out this great garden butterfly ID guide from the Butterfly Conservation Trust.

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