Jeff, you are incorrect in thinking that they are all within the same species. Of the 14 finches, they are all a different species, and they span 6 different genuses.

GROUND FINCHES
Small Ground Finch: Geospiza fuliginosa
Medium Ground Finch: Geospiza fortis
Large Ground Finch: Geospiza magnirostris
Sharp-beaked Ground Finch: Geospiza difficilis
Cactus Ground Finch: Geospiza scandens
Large Cactus Ground Finch: Geospiza conirostris

TREE FINCHES
Small Tree Finch: Camarhynchus parvulus
Medium Tree Finch: Camarhynchus pauper
Large Tree Finch: Camarhynchus psittacula
Woodpecker Finch: Cactospiza pallidus
Mangrove Finch: Cactospiza heliobates
Vegetarian Finch: Platyspiza crassirostris

Warbler Finch: Certhidea olivacea
Cocos Island Finch: Pinaroloxias inornata

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