reptile survey

Reptile Surveys – A Brief Guide

In the UK there are 6 different species of reptile; three snakes and three lizards. These animals play an important role in proper ecosystem functioning through controlling insect and rodent population numbers. Reptiles are also a source of food for many animals including hedgehogs, badgers and birds, but unfortunately all populations in the UK are in decline to some degree. Reptiles are protected under the UK judiciary system and it is an offence to intentionally or recklessly kill or injure each of the species.  The sand lizard and smooth snake, which are very rare, are further protected and require a licence when carrying out a survey in an area with known populations of each species.

The Ecology Training UK reptile course is designed to provide you with all the information to carry out a survey. There are also field visits and a chance to handle reptiles. You can find out more HERE.

Carrying out a survey

Initial Preparation

When preparing for a survey the first thing which needs to be determined is the type of investigation you wish to carry out. There are three types: presence/absence, population numbers, and monitoring.  This guide will focus on presence/absence surveys, which as the name suggests aims to determine whether reptiles are present on the site. Once the survey type is established, permission must be obtained from the land owner or manager of the site. It is a good idea before visiting the site to carry out a desk based study of reptile populations in the local area. This may have been undertaken at the preliminary Ecological Appraisal stage. The local records centre holds records and there will also be records on resources such as MAGIC map.  Preparing a map of the site and a survey form, in which sightings can be recorded (dates, species, number, location etc.) is also essential before carrying out the survey.

Survey Procedure

Surveying for reptiles is challenging because they are highly secretive and often camouflaged, with relatively low population densities. The time of year and day are restricted when carrying out surveys, as activity levels in the winter and hot months of the summer are low, making reptiles difficult to detect. It is a good idea before carrying out a survey to familiarise yourself with the basic behavioural ecology of each of the 6 UK reptile species, as this will make finding and identifying them much easier.

Reptiles are active from March to October. May, April and September the best times of the year to spot them, and during this time lizards bask in the morning from around 8.30 – 11.00 am, then from 5.00 – 6.30 pm (depending on the weather).

There are two methods for carrying out a presence/absence survey and these are designed to work in conjunction with one another– Direct Observation and Establishing Refuges.

Direct Observation

Direct Observation is the process of searching for reptiles on site. Reptiles can be found in a wide range of habitats from grass and heather heathland to suburban wasteland, but following some general rules can increase your chance of identification. Reptiles are ectotherms, this means that they require energy from the sun to warm them up in order carry out their general activity. They bask in the mornings and evenings; identifying these ‘Basking Spots’ is key to finding reptiles on a site.

‘Basking Spots’ are generally covered in short vegetation and are close to places of refuge where reptiles can hide, such as hedges or banks. When searching for reptiles tread lightly and slowly, ideally with the sun in front of you (shadows falling on lizards can scare them away immediately), and listen out for any rustling sounds. Binoculars which are able to focus in a close range can be very useful for species identification.

Establishing Refuges

Creating artificial basking refuges is a method used to increase the chance of determining the presence of reptiles on a site. These provide suntraps so to allow the reptile to warm up, therefore need to be made from materials with good conductivity such as tin or black bitumen sheets. The recommended size of a refuge is 0.5m2; these should be placed on potential ‘Basking Spots’. The number of refuges set up will depend on the size of the site under investigation. When carrying out a presence/absence survey 5-10 refuges per hectare is considered adequate. It is often more for consultancy, and depends on the project.  Seven visits are the minimum number required to determine with reasonable confidence the presence or absence of lizards, and can also indicate the size of the population (low-high). Visits should be carried out when the weather is most conducive to spotting basking reptiles. The weather should be warm and dry with little wind, ranging in temperature from 9-18ᵒC, long periods of cold followed by warm weather are ideal. To check the refuge lift one side up vertically, wearing gloves if adders are likely present, be sure to be sure to place the refuge back in the same spot. Peek underneath and record what you see.

What To Record

Record the location of each reptile sighting on your map, the species, number of each species, and the amount of time spent searching. You also need to record the life stage (adult/juvenile) and the sex, to establish if there is a breeding population on site. Determining absence of reptiles on a site is very difficult, the term ‘likely absence’ is therefore commonly used instead.

We run a reptile surveying course at Ecology Training UK that will teach you how to carry out a survey, as described above. You will also learn how to identify each of our reptile species and how to age and sex them. The Exeter course includes snake handling too! Take a look to find out more.

GOOD LUCK!

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Acorn Ecology Training

Acorn Ecology is one of the top providers of ecological consultancy courses in the UK. We provide ecology courses and field training for new graduates, career changers, experienced ecologists, developers, architects and conservationists wishing to work in consultancy.