Bennett’s Patch and White’s Paddock was Avon Wildlife Trust’s key project when Bristol was selected as the European Green Capital in 2015. The Trust has successfully turned these derelict, former sports pitches into an amazing nature reserve.

A reptile survey in 2014 by the Trust revealed a good population of slow worms on the site, which volunteers have been continuing to monitor since 2018.

The surveys are undertaken using the recommended methodology for reptile monitoring, which involves placing and then checking underneath mats (felt roofing tiles).  The mats were all located in the northern part of the reserve and were mapped using GPS, with a total of 34 mats used.

Surveys were carried out each year between 2018 and 2022, with the exception of 2020 due to Covid restrictions. Monitoring visits were between March and October each year, which is the optimal time of year for reptile surveying, as this is when they are most active.

The average number of slow worms per visit are broadly similar for each year, with the exception of 2019.  There were fewer mats in 2021 - 22 due to some mats being lost or moved, or being covered by cut material, overgrown with bramble. Some monitoring visits were also effected by the availability of volunteers to carry our survey visits.

In 2018, out of 87 slow worms only 2 were adult/sub-adult males, 29 were adult/sub-adult females and 56 were hatchlings.  The large numbers of juveniles/hatchlings is probably partly due to the number of surveys undertaken in late-summer/autumn that year.

The much higher average from 2019 is partly due to the large numbers of juveniles/hatchlings recorded, as in 2018, but it is likely that there were a number of other factors, including climate and habitat condition. 

The total of 35 slow worms recorded in 2022 consisted of six adult/sub-adult males, 13 adult/sub-adult females and 16 juveniles/hatchlings.

In the same year, an average of 30 mats over the five survey visits were re-located and monitored. Out of these 30 mats, 18 mats had slow-worms recorded under them. Between 2018 and 2022 only 4 mats were unused, which equates to around 90% of the total. 

It’s not clear why more females have been found some years, though this may be partly due to more surveys being undertaken later in the season, when more females would have been emerging.

Future threats to the population here include loss of suitable habitats, such as dense scrub/bramble for refuge and hibernation, and edge habitats for basking. There's also the threat of disturbance from people and dogs.

Other species found under mats includes great crested newts (in May/June 2022), palmate newts, toads, voles, ants, woodlice and a variety of other invertebrates.

We would like to thank all the volunteers who have assisted with the surveys over the past 5 years:   

• Tim Clarke
• Heather Clarke
• Ka’ia Bellamy
• Richard Bewley
• Nikki Morgans

2023 surveys will start in April and continue until October.

Unlike other UK lizards, slow worms are less likely to bask in the open preferring instead to bask half hidden in dense deep vegetation.  In very warm weather they will take refuge underground or in thick vegetation.  However, if you get up early on a summer’s day before it gets hot you will have a chance of observing them.  Alternatively, carefully look under stones and rocks.

Slow worms are carnivorous and feed on a variety of invertebrates, including slugs, snails, spiders and insects.

Slow worms play an important role in the ecosystem as both predators and prey. They help to control populations of insects and other invertebrates  Slow worms are also a source of food for birds of prey and other predators.