Robust and rapid ways of assessing and monitoring forest biodiversity are increasingly necessary. To this end, we present a classification of forest birds in Kenya and Uganda into three simple categories: forest-specialists (FF species), forest generalists (F species) and forest visitors (f species). FF and F species, but not f species, are dependent on forests. Out of 479 forest birds in the two countries, 214 are FF, 156 F and 109 f species. Forest-dependent birds, and particularly forest specialists, are less widespread than forest visitors. Uganda has 420 forest birds compared to Kenya's 335, and a higher proportion of forest specialists: this reflects differences in forest structure and biogeography, rather than the area of natural forest. Using this classification allows species lists and densities to be interpreted more meaningfully. The number of FF species is an initial measure of a forest's relative conservation importance, while the proportion of FF, F and f species and their relative abundance will shift according to changes in forest structure.