The results of factor analyses for the life-history traits of host species.

<p>A. Factor analysis for mammal hosts of Lyme disease. B. Factor analysis for bird hosts used in WNE-1. C. Factor analysis for bird hosts used in WNE-2. D. Factor analysis for bird hosts of EEE. Species codes plotted in ordination space reflect the first two letters of the genus and species names (for Lyme disease, the species codes cannot be given because the species' names of the internal nodes were not available).