A grass snake (Natrix natrix) in the set-aside at the top of Kestrel Field.
This is a youngster, no more than 30-40cm long, perhaps one of last year’s hatchlings. Mature adult females, which are larger than the males, can reach 1.5 metres: Britain’s longest native snake. They are non-venomous and will not hurt you.
Grass snakes come in a variety of greenish colours from pale olive green to almost black. They have black bars down their sides which can vary in size and show up more on lighter coloured individuals but they all have a distinctive cream collar between their head and body.
They are strong swimmers and in ponds and streams, favoured habitats, they prey upon fish, frogs, newts and tadpoles of all kinds; up in the Kestrel field set-aside, they will be hunting small mammals and baby birds. The field vole colonies up there, with nests full of babies, will be a major food source at this time of year.
Grass snakes hunt using sight and their sense of smell. They use their tongue to smell the air. It was once thought that they used only their tongue to smell but now we know they can also use their noses in some circumstances.
Grass snakes are Britain’s only egg-laying snakes. In June and July the females lay clutches of 10-20 eggs in rotting vegetation. The heat generated by the composting process incubates the eggs, which take between six and ten weeks to hatch depending on just how much heat is generated. The newly hatched snakes are totally independent of their parents and begin their hunt for food and shelter immediately.
Pictures by DKG
Conservation status: Protected in the UK under the Wildlife and Countryside Act, 1981. Priority Species under the UK Post-2010 Biodiversity Framework.