it is a cobalt blue lineolated parakeet, better known as a linnie.single dark factor
I use to own 3 of them, 1 creamino, 1 cobalt blue, 1 mauve, (double factor)
they are a hidden jewel of birds. they are amazing climbers, slow like a parrot, smart, and have wonderful temperments.
the only thing you have to watch for is they love to hide under blankets, cushions, etc...
many have died due to owners not knowing they are hiding under things and they get sat on and crushed