Forest of Marston Vale – Fascinating Reptiles

A GUIDE TO

The UK’s six reptile species are often overlooked. Their shyness and increasing rarity means they are seldom encountered, but if you are lucky enough to stumble across one it is sure to make your heart beat a little faster!

Reptiles can tolerate the peripheries where mammals struggle to succeed, and are great indicators of the health of our habitats. Sadly, all are suffering declines due to loss and degradation of habitats, continual fragmentation of populations and persecution, so it is crucially important that we protect our precious reptile populations now.

In Bedfordshire these four native reptiles can be found in Bedfordshire, including the adder; Britain’s only venomous snake, the grass snake; known for its aquatic lifestyle, the slow-worm; a legless lizard that is often mistaken for a snake, and the common lizard, which sheds its skin each year.

Adder

Although venomous, the adder is not aggressive, choosing to retreat from disturbance rather than face confrontation. Even when harassed the snake often hisses and warns well before striking. A small and chunky snake, adders typically measure around 50cm. Males are pale grey and females are usually brownish with orange and red shades. Adders have red eyes and a distinctive brown zigzag down the spine, which is darker in the males.

To feed itself, the adder sits motionless and waits for small mammals such as voles or mice to pass by, relying on its camouflage. On striking, it waits for its prey to retreat and die and then follows the scent of its own venom to find it. It will also feed on small birds and lizards.

It favours sheltered areas where it can bask in warm sunshine, such as woodland clearings, glades and edges, heathland, moorland and areas of open scrub, bramble and gorse where it can hunt and commute in relative safety from predators.

Adders give live birth to between three and over a dozen young. They are usually born between August and October. From October, adders go into hibernation and usually emerge in the first warm days of March, which can often be the best time to spot them.

Grass snake

The grass snake is the UK’s largest and commonest snake. It prefers wetland habitats, and good places to look for them include clean, slow-

BEDFORDSHIRE’S FASCINATING REPTILES

flowing rivers, canals, lakes and ponds. The grass snake is a strong swimmer and its diet consists mainly of fish and amphibians, although it will also eat small mammals and young birds. Occasionally grass snakes are seen on heathland sites too – especially the larger females that can tackle mammals and other reptiles.

The grass snake can be identified by its grey or olive-green body and yellow and black collar. Another distinguishing feature is its round pupils (adders have vertical slit-shaped pupils). Females typically grow to around one metre, while males reach around 70cm.

Females lay between 10 and 40 eggs, favouring warm, rotting piles of vegetation in which to incubate them. They sometimes choose garden compost heaps in which to lay their eggs. If you’re lucky enough to find a grass snake in your heap, you can cover the heap with an old piece of carpet to provide extra protection from predators.

Slow worm

The slow worm is sometimes mistakenly referred to as a grass snake. Although it resembles a snake it is actually a legless lizard. The slow worm is smooth, shiny, and a metallic golden brown in colour. The females have darker flanks and a stripe down the back, and very occasionally individuals can be found with blue spots. They are small, usually measuring between 30 and 40cm. They have blinking eyes and fragile tails that can break as a defence mechanism, like most lizards.

Lizards are particularly fond of hunting on warm days after rainfall when slugs and earthworms can be caught. It is regularly found in allotments, gardens and on rough grassland, but is most often encountered on heathland sites and insect-rich unmanaged grasslands, particularly heathland and woodland edge habitats. It lives mainly out of sight under the grass thatch and among thick vegetation where it can hunt invertebrates. The slow worm is less likely to be seen out in the open, as it gains heat and energy while basking underneath vegetation, leaf litter, timber or rocks.

Common or Viviparous lizard

The common lizard is generally small, measuring about 15cm. It is variable in colour, but most are brownish-grey, often with rows of darker spots or stripes down the back and sides. Males have bright yellow or orange undersides with spots, while females have paler cream bellies with stripes.

It is found in warm, insect-rich habitats, often unmanaged with plenty of diversity and dead wood.

Main habitats include heathland, moorland, scrub, woodland edges and geological scree sites. Like the adder and slow-worm, the common lizard gives birth to live young. This way the eggs are not at the mercy of erratic spring and summer weather, and the mother can carry them into warm areas or hide underground when surface temperatures are too cold. The young are born around July, when the insect population is usually at its highest.

If you do encounter a reptile while out and about – especially on one of our sites – we’d love to know about it. Your sightings will help inform our conservation work, and build up a picture of populations in our county! Email info@marstonvale.org