From scaring endangered birds on their nests to the mountains of excrement they produce each day, dogs with irresponsible owners are a growing problem in UK nature reserves, say conservationists, who are urging owners to keep their pets on a short lead. The Wildlife Trusts, which operate more than 2,300 nature reserves across the country, say loose dogs are a leading cause of plant and animal disturbances in the UK reserves and their waste carries diseases for wildlife, with growing evidence that the 3,000 tonnes of faeces and urine produced by dogs each day disturbing the balance of ecosystems at…