The latest research from the British Trust for Ornithology (BTO), just published in the journal Global Ecology and Biogeography, shows that the diversity of Britain's birds has increased with a warming climate, but this was accompanied by a loss of habitat specialists. Using Breeding Bird Survey data from 1994 onwards, scientists at the BTO found that recent temperature increases had a positive effect on the number of bird species. However, rising temperatures also had a negative effect on species with specific habitat requirements or 'specialists'.
It appears that the winners from recent climate change were already common habitat-generalists that have expanded their ranges, likely at the expense of habitat-specialists such as the Grey Partridge and Corn Bunting, which have declined by 50% and 29%, respectively, over the period of the study. Overall, this means that with climate change, bird communities across the UK are becoming more similar to each other as vulnerable range-restricted species are outcompeted by more resilient common species.
Alison Johnston from BTO commented: "This study is one of the few which has looked at the overall impact of recent climate change upon bird communities, and the first such assessment for the UK. It provides stark evidence of the impact that climate change has already had on the birds we see around us. The winners are those species that are already common and widespread, while more specialised, rarer species have lost out. If these processes continue it will lead to the homogenisation of bird communities across the UK. Whilst most studies on the impact of climate change on bird communities in the UK have focused on single species, this is one of the first to explore how future climate change may continue to impact on bird communities across a large spatial scale."