One of Britain's rarest animals is being put under threat by people trying to catch a glimpse of the creature.
The Lincolnshire Wildlife Trust said several adders had been found after apparently being killed with sticks.
The snakes are also being disturbed by people going off paths to try to have a look at them. The adder is Britain's only venomous snake.
The trust said the snake's bite was unlikely to be fatal and they should be left in peace as much as possible.
Rachel Shaw, from the wildlife trust, admitted it was ironic the threats to the animals seemed to come from people who were scared of the snakes and people who were interested in them.
She said: "Adders are quite timid and only attack when frightened. They are a declining species and any deaths are very unfortunate.
"It is understandable that people want to see these animals but instead of staying on the paths they start tramping through the vegetation and turning over things to find them.
"Adders are creatures of habit, in the sites they like to go to and hunt in certain places and if these are disturbed then it can affect how much food they are getting."
Ms Shaw said only 12 people have been killed by adders in the past 100 years.