be birds of the same feather

To be very similar (to another person) in taste, preference, opinion, etc. I knew you and John would get along well. Given all the interests you share, it seemed pretty clear that you were birds of the same feather. Janet and I have always been birds of the same feather. There's very little that we don't agree on. Jenna and the new receptionist are both so organized and meticulous. They should work well together given that they're birds of the same feather.