Large Ground Finch
Geospiza magnirostris
The large ground finch weighs about 27–39 g (0.95–1.38 oz), and its length ranges slightly 15–16 cm (5.9–6.3 in). It is the largest species of Darwin's finch both in total size and size of beak. The feather and bill colors vary between males and females. The adult male is mostly black, with slightly browner wings and tail; the cloaca is white-streaked; the eyes are dark brown. It also has blackish legs. The tail is relatively short.
ID text from Wikipedia, CC BY-SA 4.0
Medium Ground Finch
Geospiza fortis
Like the other members of its genus, the medium ground finch is strongly sexually dimorphic; the female's plumage is brown and streaky, while the male's is solid black, with white tips to the undertail coverts. The bird measures 12.5 cm (4.9 in) in length—which falls between the lengths of the small and large ground finches. The bill of this species is quite variable in size, though the length of the upper mandible is always greater than the depth of the bill at its base. The wing shape, on average, seems to change with ecological shifts.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Large Ground Finch and Medium Ground Finch.