Fig. 2.

Average taxonomic composition of gut microbial communities of Darwin’s finches, from Illumina 16S rRNA gene surveys, based on OTU clustering at 97% identity trimmed to at least 1% relative abundance in at least one finch. Data is grouped by season, island, and species. The colored bar at the bottom, which also shows sample sizes, distinguishes finch samples from the dry (red) and wet (blue) seasons (Note that for this analysis, Santa Cruz, and neighboring islands Santa Fé, and North Seymour are grouped together as “Santa Cruz +” ). An average of 25,382 reads per finch, comprised of 297 unique OTUs (clustered at 97% similarity level), was recovered at greater than 1% relative abundance in at least one finch across the dataset