All creatures of the same species look alike, and it takes a lot of observing to tell them apart. The two tea-colored Societies in the photo below are very different: the one on the left has a white "cap" on his head, and the one on the right has white "eyebrows."
The problem is, I have two tea-colored birds with white caps, and two tea-colored birds with white eyebrows. I tell Tea and Darjeeling (white caps) apart by looking more closely: Tea will sing his Hunka Hunka Burning Love song, and dance his Hunka Hunka Burning Love dance, plus he has a line on the right side of his beak. But, you can't tell either of those things from this photo. Until I started telling their stories in this Finster Log, I never really had to pay closer attention than that.
Earl Grey and Decaffeinated (white eyebrows) also have subtle differences: Earl Grey sings and dances, and Decaffeinated has a broken back toe that curls up. Again, this photo doesn't show those differences, so I'll have to start watching them more closely. I think
Decaffeinated is on the right, because that bird seems a little bigger from this angle, and Decaffeinated, at a porky 20 grams, knows a tasty seed when she sees one. But I could be wrong. (That's Bosco's tail in front of the bird on the right.)
I've figured out the differences between Earl Grey and Decaffeinated. Earl Grey has more white on his throat and below his eyes. So, in the top picture, it's Earl Grey on the right, and in the bottom picture, it's Earl Grey on the left. The power of observation.