The little ruddy Ring-Dove is distinguished from all other species by its long wing, with the first primary nearly or quite equal to the second, and by having the sexes dissimilar in plumage. Two species are generally attributed to this group, but I cannot see that they are sufficiently distinct to deserve separation.
The Fauna Of British India, Including Ceylon And Burma-birds
Blanford, William Thomas, ed. The Fauna of British India: Including Ceylon and Burma. Vol. 4. 1898.
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