Surveys, Monitoring and Records

                                                                                                                         Download Recording Forms

Downloadable forms for Transect Surveys, Site Surveys and Casual Records, plus instructions for Casual Records, are at this link. 

Records are entertaining to keep, interesting to look back on and they help conservation enormously. If we don’t know how species are doing, what is thriving and what isn’t, we cannot hope to halt and reverse declines.

In this section we explain where to send your casual records, how to get help with identification and how to become involved with surveys and monitoring.

Your butterfly records

All records are useful. A glance at the map below will show that there are plenty of white squares around Bristol and Bath and in Somerset where nobody has sent us a record of any butterfly during the last 5 years. That means that the distribution maps are far from complete and that records made on your daily dog walk may be filling important gaps in our knowledge. People who go further afield in places like Exmoor, on the Mendips or in the woodlands of the Blackdowns may find colonies of scarcer species never before documented.

So please do make a note of what you see and email to the County Butterfly Recorder at

Better still, put all your records for sites you visit on a Casual Records form and send in at the end of ther season.  

If you see a butterfly you can’t identify, try to get a photo and then go to the helpful guide at the main Butterfly Conservation website or go to our Facebook or Twitter pages. Somebody will be able to tell you what it is.

The National Garden Butterfly Survey

The National Garden Butterfly Survey provides invaluable information on the populations of our commoner butterflies and, in some years, records remarkable numbers of migrant species including Painted Ladies, Red Admirals and Large Whites.

It is also interesting to see how well your own garden works to support butterflies and perhaps guide your ideas about making it more attractive for them.

It is also interesting to see how well your own garden works to support butterflies and perhaps guide your ideas about making it more attractive for them.

All you need to do is record the first date on which you see one or other from a list of 22 species in the periods March to May, June to August and September to November.

You can download the Recording Form for the survey and get an identification chart from the Big Butterfly Count website

The Big Butterfly Count 

This is a nationwide survey aimed at helping us assess the health of our environment. It was launched in 2010 and has rapidly become the world's biggest survey of butterflies. Over 44,000 people took part in 2014, counting over half a million individual butterflies and day-flying moths across the UK.

Butterflies react very quickly to change in their environment which makes them excellent biodiversity indicators. Butterfly declines are an early warning for other wildlife losses. The count also assists us in identifying trends in species that will help us plan how to protect butterflies from extinction, as well as understand the effect of climate change on wildlife.

The count takes only a quarter of an hour to do and you do not need to be an expert. If you are unsure about identifying butterflies, you can download a free identification chart from the national BC website

Records from all types of places add to the picture. And even if you record nothing, that adds to our understanding of species distribution and trends, so “nil returns” are as useful to us as a long list would be.

Details of dates for 2016 will be posted next summer. You do not need to contact the Branch to participate in the Count.

Transect Walkers

Transect Walkers help to monitor all the butterflies in selected sites throughout the summer. This provides information on changes in the abundance and status of butterflies throughout the UK and also helps guide the management of many nature reserves, not only our own but those of the National Trust, the Wildlife Trusts, the Woodland Trust, RSPB and others.

Butterflies are recorded along a fixed route (a transect) on a weekly basis from the beginning of April until the end of September. Transects are typically about 2-4 km long, taking between 45 minutes and two hours to walk. They have to be visited between 10.45am and 3.45pm and only when weather conditions are suitable for butterfly activity.

Due to the vagaries of the weather, it is rare in practice to achieve a full set of 26 weekly counts even if you have no other commitments and can visit the transect at any time in the week It is best to take on a transect as part of a team of several people. In fact, it may best to begin by helping an existing team, so as to learn the methods and develop the field skills required.

Transect monitoring is run by the UK Butterfly Monitoring Scheme, a joint project between Butterfly Conservation, the Joint Nature Conservation Committee and the Centre for Ecology and Hydrology with funding by a multi-agency consortium led by the Department for Environmental Food and Rural Affairs.

The Branch has a Transect Organiser (see the About Us page for contact details). Transect recording forms are at the link at the top of this page. Each year we publish a report with the full results from our area. Click here for the 2015 report 

Single species transect surveys

Single species transect surveys are especially useful on nature reserves with one or more uncommon species that are the direct object of management.

The transect must follow the standard method and be carried out at least once a week throughout the flight period and more frequently if possible. The focus on a single species of course reduces both the time required to walk the transect and, more significantly, the number of weekly counts that are needed.

Timed Count Monitoring

Unlike transects, timed counts need only be carried out once a year at a site to provide meaningful results which makes then a useful ‘reduced effort’ method for monitoring rare butterflies, especially those whose distributions change over time across large sites. 

The count must be done as near as possible to the peak flight period of the species in question. As with transect walking, timed counts should ideally be made between 10:45 and 15:45 and suitable weather is essential.

First, quickly walk the site to identify the extent of the adult flight area. If adults are patchily spread over a large area, it is better to identify sub-populations and survey them separately. Then count adults by walking the site, either in a series of parallel lines or in a zigzag path, covering the flight area as thoroughly and evenly as possible. This usually takes between 5 and 60 minutes depending on the size of the colony area.

It is important the walk passes through areas of high and low adult density: If only the best patches are visited, analysis may over-estimate abundance.

Our Branch’s Transect Organiser can give more guidance, see the About Us page for contact details.

Moth records and surveys

There are plenty of day-flying moths and some of them are brilliantly coloured and easier to identify than many butterflies, so you do not need to trap moths or struggle with identification to build up a worthwhile list of species.

Moth records are of great value – arguably more so as there are many more moth species than butterflies and their distributions and trends are much less well known. Records and photos can be uploaded at the Somerset Moth Group website

If you want to do more with moths, trapping events for beginners are run by the Moth Group, see the Events section.