a) The importance of each major habitat type for all bird species

Birds are found across the world in all major habitat types. Although some birds occur in two or more habitats, many specialist species are confined to just one. Grasslands, savanna and inland wetlands are all important habitats for birds, each supporting about 20% of species (see figure a), while shrublands support 41% of birds. Around 48% are found in ‘artificial’ terrestrial habitats; those that have been modified by humans such as agricultural land, but by far the most significant habitat is forest, supporting 77% of all species (analysis of data held in BirdLife’s World Bird Database 2016).

Birds are found in all forest types, from subantarctic woodland to equatorial rainforest (see figure b). The most important types are tropical/subtropical lowland and montane moist forest, which support 52% and 38% of species respectively, with tropical/subtropical dry forest supporting 20% (analysis of data held in BirdLife’s World Bird Database 2016).