For the first time, a team of researchers from Sweden has discovered a link between the immune systems of different bird species and the diverse climatic situations in which they survive. Swedish researchers believe that as the climate changes, some birds become prone to diseases that they are not habitual to handle. The outcomes of the study reveal that evolution has regulated the immune systems of several bird species over millions of years, allowing them to deal with conditions specific to the particular environment and climate in which they reside.