Tale of two pigeons: Woodpigeon blamed for demise of rival Paul Stancliffe said: "People seem to either love woodpigeons or hate them when they come into their gardens. They are a big presence and people do sometimes think they come in and bully all the other birds away, with their sheer size. It could be that they are pushing out collared doves. At the moment, we are not clear exactly what the relationship is between the two things but it is interesting that one is doing so well and one so poorly, when they occupy the same ecological niche. As well as its larger size enabling it to outcompete the collared dove for food and habitat, another factor favouring the woodpigeon could be the impact of trichomonosis, a disease affecting many bird species, which has spread in recent years. Collared doves appear to be more susceptible to it than their larger rivals. Woodpigeons have done particularly well in south east England and East Anglia, and experts believe this could be linked to changes in agricultural practices. A switch from spring sown to autumn sown cereals and the introduction of oil seed rape means more food is available all year round, leading to more birds surviving the winter and a longer breeding season. Clare Simm, from the BTO's Garden BirdWatch, said: "The weekly records from over 14,000 BTO garden birdwatchers provide us with fascinating insights into the ever-changing world of birds. Woodpigeons seem to be the latest big winners but we are losing collared doves, greenfinches and starlings.