Fig. 3
From: The gut of the finch: uniqueness of the gut microbiome of the Galápagos vampire finch
a δ15N vs. δ13C isotopic composition of feathers from Darwin’s finches, specifically the vampire finch (G. septentrionalis from Wolf Island; red triangles), medium ground finch (G. fortis; San Cristóbal Island; green squares), and small ground finch (G. fuliginosa; San Cristóbal Island; green circles), in comparison to other animal tissues (grey dots). For the finches, each symbol represents values recovered from one individual bird. Error bars, where present, indicate the range of values obtained from two to three different feathers from the same individual. δ13C for ground finch feathers ranged from − 24.1 to − 18.7‰ vs. PDB, and from − 23.8 to − 16.1‰ vs. PDB for vampire finches. δ15N ranges from + 4.9 to + 11.7‰ for ground finches and between + 14.2 and + 25.1 ‰ δ15N for vampire finches. The vampire finch feathers differ significantly in δ15N (ANOVA p < 0.0001), but not δ13C (ANOVA p > 0.9). Isotopic values from other animals were reported in the following: [44,45,46, 78,79,80,81,82,83,84,85,86,87]. b Non-metric multidimensional scaling (NMDS) ordination of three species of gut microbial communities of Darwin’s finches according to diet. Taxonomic (OTU) clustering is at 97% identity and abundance weighted by taking the fourth-root of the OTU relative abundance in each finch