These two beautiful blue birds are spring migrants, sometimes seen during breeding season in the same
locations in the eastern and central part of the US. In certain light, they can look very similar. So to tell them apart, check out how they compare:
1 – Size: Indigo Buntings have small round heads, are the size of a sparrow and are smaller than the chunky Blue Grosbeaks
2 – Beak: Grosbeaks are known for their thick bills, while buntings have a smaller more cone-shaped beak
3 – Field Marks: A Blue Grosbeak in full breeding plumage is a deep blue with chestnut colored wingbars, while the breeding Indigo Bunting male will be a beautiful blue all over with a slightly darker blue on his head and darker wings. Non-breeding Indigo Bunting males may have rusty patches on their bodies and sometimes on their wings. If you see this, then look at the beak to make the final determination.