The birds in the picture are love birds. I don't know what the ones all together are called, but the lonely one looks like it is a peach face love bird. You can't sex love birds by their appearance and birds aren't really known for disliking certain genders, so that's probably not it. Probably, the birds were scared and huddled together in the corner. Maybe the last one is braver or just wasn't in the corner yet when the picture was taken. I've also seen this with my guinea pigs. When I lift the hut, they will run to a corner and huddle together, but sometimes one just leans up against the wall.

It's hard to tell from the pic; but, YES, they do look like the same kind!!! As to the WHY, I cannot tell you unless I was there when they took the pic!!! It may have been that the photographer staged the pic just so they could get it put in the internet. The male might be a bully that has attacked the females too many times. I'm sure there are other explanations that I haven't named so far!!!

It looks like to me the male has the others where he wants them. They may be younger and don't want any trouble.

A little tacky, but yes they are all lovebirds, just different colors.

if so why do they act this way