As the landscape changes and threats to bird populations morph over time, trends in suites of bird species can reflect or illuminate general patterns of change in different habitats and other breeding resources. Evaluating bird species that share similar resources, as a group, can also bring to light potential problems underlying bird population declines that a species-by-species approach may not reveal.
Habitat-based bird groupings in this discussion are not intended to collectively include all species that may occur in the habitat described. Species that do not fit wholly into a habitat group because they frequently use other habitat types are not included. For example, Song Sparrow nests in grasslands, but it also nests in shrub/edge habitat, so it is not included in either group. The intent of this approach is to focus on species that specialize in only one of the habitats listed, to serve as the best indicators of the status of that habitat. Groupings used here that are based on other characteristics such as foraging strategy, however, may include some of the same species that are found in a habitat group.
Discussion about changes in block occupancy between the first and second atlases refers to Priority 1 blocks only, unless stated otherwise. A discussion about management for each of the following species group can be found on the Bird Conservation page.