Water pipits are strange creatures, in that some of them move north for winter! But places like England and Wales are still presumably warmer in winter than high up a mountain in northern Spain (where they breed). In one location in north Wales, they were observed to favour watercress beds! In other places they were found on sewage farms. (2) They feed on insects and snails which presumably can be obtained throughout the winter in wet places such as this.
I am a retired entomologist with a background in quarantine pests and invasive invertebrates. I studied zoology at Imperial College (University of London) and did a PhD on the population dynamics of a cereal aphid (Metopolophium dirhodum) in the UK. I spent 5 years with the British Antarctic Survey studing cold hardiness of Antarctic invertebates and 17 years with the Food and Environment Research Agency. My main interests now are natural history, photography, painting and bird watching.