Instructions

In addition to this set of instructions you should have received a recording form.

Introduction

Thank you for volunteering to participate in the Essex Glow-worm Survey which is kindly supported by Essex Wildlife Trust and English Nature. The Glow-worm Lampyris noctiluca is a beetle, which belongs to the family Lampyridae. Females emit a green glow at night with which they attempt to attract flying males. It is the female’s light that make this species easily detectable for a few weeks primarily in July and August although some may be spotted as early as May and as late as October. The distribution of glow-worms in Britain could be described as widespread but local and some authors state that there may have been a steady decline in the British glow-worm population since the 1950s. However, there is little statistical evidence of such a decline, as this nocturnal species is only easy to record for a few weeks of the year. In Essex glow-worms have been described as rather rare, although national enthusiast Robin Scagell describes the county as under-researched.

The primary aim of the 2001 survey is to ascertain the current distribution of glow-worms in Essex and also to highlight the main habitats utilised. Participants are asked to count glowing females along a chosen route on three occasions during July and August.

The survey

The survey involves walking a route or transect of your choice and recording any adult female glow-worms that are noticed on three evenings in July and August. Surveys can be conducted at any site although if there is a known glow-worm colony in your area then that would be ideal. However, if you know of no local sites then an area of suitable habitat can be selected and the survey conducted. Suitable habitats include unimproved meadows, disused railway lines, churchyards and roadside verges on unlit country lanes. Even if no glow-worms are seen, the results are still valuable as it is important to know which habitats do not support glow-worms.

Creating the transect – daytime visit to the site

Once a suitable area has been selected a route or transect at least 100 metres in length must be created. A visit to the likely site during the daytime allows a rough sketch map of the site to be drawn and the route that is to be walked marked on it. A six figure Ordnance Survey grid reference is required for the start point of the transect and it is also very important to indicate the approximate length of the transect in metres (Section B on recording form). The sketch map must include a north arrow and give an indication of scale and can be drawn in Section E of the recording form. It is important that all the habitats present along the transect are noted in Section F of the Recording Form during the daytime site visit.

The night-time transect walks
[These instructions were compiled for the 2001 survey and no longer apply. Carry out your survey as often as feasible during the glowing season, June to August inclusive.]

The transect is to be walked on three evenings in July and August and the number of glowing females seen along the transect noted in Section C of the recording form. The periods within which each transect walk must be made are:

^{Each transect walk must start between 22.00 and 23.00 hours and have finished by 00.00 hours. The start and finish time of the walk must be recorded in Section C. Before the start of the walk the weather conditions should be recorded and noted in Section D. An air temperature reading in degrees Celsius (°C) should be taken using a thermometer. Also fill in a code from the table below for cloud coverage, wind speed and rain conditions before you start the transect.}
 

^{What to record whilst walking the transect}

^{Once you have started walking the transect you must count every glowing female that you see. It is advisable to walk at a slow pace so that no glow-worms are missed. Once you have spotted glow-worms note their approximate position on your rough sketch map (in Section E on the recording form). It is important to be sure that the source of any glow is in fact a female glow-worm, as other animals such as centipedes can emit a luminous fluid. Female glow-worms can be identified by torchlight. A female glow-worm with the approximate size is shown below:}

^{It is believed that artificial lighting affects glow-worms by distracting flying males which are searching for glowing females. It would be very useful if the presence or absence of any artificial lights could be noted in Section H on the recording form. This can be easily done during the walk. We are also interested in which habitats the glow-worms are using and these can be recorded on Section F of the recording form. This again can be easily done whilst walking the transect.}

^{Equipment needed for the survey}

^Torch

^{Recording form and pencils/pens}

^{Thermometer for recording air temperature}
 

^{Safety at night}

^{Participants should not put themselves in a position which could place them or others in danger. It is very important that at least two people conduct the night-time transect walks for safety reasons. Writtle College or English Nature does not take any responsibility or liability for any actions and subsequent consequences from the activities of survey participants. Do not attempt a survey on private property unless permission to survey has been gained from the landowner.}