Last night, Thomas was giving them both head pets as he was going through a catalog. As soon as they saw the camera, they looked up. It looks like he's threatening to get them!
Later on, Thomas had our lentil soup dinner cooling on the counter. Sometimes they fight over the same food, even when there is more than enough to go around. This time, they pleasantly surprised me by each going to their own bowl:
Edit to answer this question from Jonathan:
Hi, did you always have the two together? I have a budgie who was the most affectionate thing for the longest time. Finally I got her a partner and it was like I no longer existed. Every now-and-then she flies over and nibbles at my ear but that's pretty much it.
Now I have a Grey who is way more affectionate than any creature we've ever been around. She follows me all over the house, takes showers with me, cuddles... all of that stuff. I'd like her to have a playmate but I'm pretty selfish at the same time.
I did not always have the two. I have had my timneh for almost 8 years, and my congo for about a year and a half. I believe they are about the same age and they are both female. Here is the entry from when we first brought our congo into our house (we subsequently changed her name to Stella, but it's the same parrot!)
I think they enjoy having another grey in the house, but they are by no means friends. There is almost no physical interaction between the two of them. They never preen each other and are rarely closer than 6 inches, and frequently much further away than that. They chase each other around, and it often feels more like sibling rivalry than any kind of friendship. Some other of my old posts that might interest you are: this one, this one, and this one. I write a lot about their relationship with each other because it fascinates me, so if you search through the archives, you'll find many others about them!
They do mimic each other, call back and forth, and seem to prefer to be in the same room. Though I'm not sure if that last part is because they want to be near each other or because they want to keep an eye on what the other is doing to make sure she's not receiving special treatment! They are obviously caged separately.
The thing is, you never know how an existing bird will react to a new bird until you bring the new bird home. And even then, the relationship evolves over time. The best thing I can say is to only get another bird because you want one, and not as a companion for an existing bird. They may bond to each other and then eschew humans, as your budgies did. Or the opposite may happen and you may have to keep them separated so no one gets hurt. Or they may completely ignore each other, as my two caiques do. You just never know.
Adding Stella to our house did not in any way diminish the relationship we had with Max, though we are very careful to keep up the same level of interaction we had with Max before we brought Stella home. However, we did know it was a possibility that Max would choose another grey over us.
For us, the situation turned out just about perfectly in that we have two greys that desire human companionship, while having some kind of relationship with another of their species.
Also, and this is just based on my experience volunteering at the parrot rescue, it seems much more difficult to keep paired smaller birds (budgies, tiels, lovebirds, parrotlets, aratinga conures) tame than paired larger birds. I have met pairs of macaws, amazons, and greys that were devoted to each other, yet still tame to people. It all depends on the individual characteristics of the birds and, to a certain extent, the work that their owners are willing to put in to keep them tame.
I wish I had a more definitive answer for you, but as so often when you're dealing with these intelligent creatures, it's not cut and dried!