EP11 comparison! tv on the left and bd on the right (x) note: the last two bd pics were clearly distorted from the camera lens, so i fixed them a little bit according to how the backgrounds should look (ie no bendy walls/reflections)
There’s two sides to the symbolism of parrots that I can find – the perspective of them domesticated, and the perspective of them wild. The first applies to Lewis and the latter to kastle, IMO. All the reasons that they are a haunting reflection of Lewis are the flip-side for why they’re beautiful for kastle.
When these birds are domesticated, they are put into cages, are subjugated, and thus lose their instincts. They are seen as symbols of weakness, mindless repetition, lack of own thought/creativity, and even depression/emptiness. For Lewis, the parakeets kept trapped in their cage foreshadows where his misguided path ends up. In the end, he remains as weak and hopelessly near-sighted as those trapped birds that refuse to leave out the window and he ends his life in his own cage, both metaphorically within his mind and literally within the sealed-up refrigerator.
The symbolism of the birds free is much more pure and positive. Across their many native lands, they are associated with finding direction/guidance, the sun, strength/protection, loyalty/love (parrots mate for life), and immortality. For kastle, the visual comparison of the parakeets facing each other in their cage and in a near-forehead touch at that is an echo of Frank and Karen later staring and pressing close together in the elevator. But moreover, the birds staying together could represent the strength and loyalty they have within each other. There’s also the relation between the symbolism and how they end up in that elevator in the first place – protecting each other, Karen following Frank’s guidance with the wires and Frank following Karen’s directions with the fake-hostage situation.
I think the free symbolism could be applied to kastle (again, whether intentionally done or not) because of how they end compared to Lewis. Lewis ends in his cage – but kastle own their cage (the elevator), they’re the ones that chose it, and from there they find a deciding moment of support within the other before each go freely, Frank through the roof and Karen through the door. They make it out. They’re not trapped in there – they never were, it was nothing more than an illusion. (There is definitely further conjecture that could be made about the sun-linked symbolism, and the association of immortality with each of them and all they go/have gone through, and etc, but I’ll just leave this here!)
[ **And I would be very remiss not to point out that this is now the second symbolism of TP (first being the white roses) we’ve stumbled across associated with long-standing loyalty/love, lol ]