Congo vs. Timneh physical characteristics

A few weeks ago, I said I would try to get photos of my greys' tails to help illustrate the physical differences between congos and timnehs.

Here's Max (timneh):

Here's Stella (congo):

In addition to the color of their beaks, one of the most striking differences is their tails. These tail feather molted naturally (I'm saving them to send to this project).I've noticed some personality differences between my girls, but those are not necessarily due to the fact that they are a congo and timneh -- my caiques also have many personality differences! But there are also many similarities between my greys. Probably the best personality similarity is that they are both very loving!