We have taken a conservative approach to summary of population changes in species that have undergone taxonomic changes during the BBS period. Because the only changes that can be made by data managers are geographic in nature (e.g., renaming species where clear geographic distinctions exist), the analysis is not changed for those regions by the name changes. However, by analyzing them in aggregate, we can use all the information from areas where the taxonomy is uncertain. Investigators can extract information for "split" species by viewing the population change summaries at the scale of the geographic species.
Here is a list of the grouped species. The name of each grouped species complex is followed by the component species.
Great Blue Heron Ardea herodias
Mallard Anas platyrhynchos
Red-tailed Hawk Buteo jamaicensis
Tufted Titmouse Baeolophus bicolor
Yellow-rumped Warbler Dendroica coronata
Dark-eyed Junco Junco hyemalis
Western/Clark's Grebe Aechmophorus spp.
Sapsucker (3 species) Sphyrapicus spp.
Willow/Alder Flycatcher Empidonax spp.
Pac.-sl./Co. Flycatcher Empidonax spp.
Northern Flicker Colaptes spp.