Found her today.

[EleriDragonfly]

I came home from work today to find my budgie Amaterasu dead on the floor of the cage. I cried for about 10 minutes straight with her in my hands. I'm guessing she must have been ill, though she was fine yesterday and this morning, eating and playing like she usually does.
Judging by the droppings I'm guessing she must have been laying at the bottom of the cage for a while, which just makes it worse. My other budgie Wheatley doesn;t seem phased, even though they both seem to have bonded. They'd preen and feed each other. Though when I put her body down to try and find something to put her in, Wheatley went up to her and started preening her. I removed her instantly but I can't tell if he knows what's happened.
I'm going to call the vets tomorrow to try and book an appointment for tomorrow evening to see if they can shed light on what killed her. She'd only just turned 1 as well, here cere had started to change colour. Even though she was a loud budgie, she was a funny little thing. Hanging upside down from the cage, climbing all over her toys. I'm going to miss her.

[cml]

I am very sorry for your loss ...

[Utoomom]

....so, so sorry~~poor little angel...hope you heal fast.

[Andromeda]

I am so very sorry about your bird.

I know this is morbid but if you plan on bringing her in for a necropsy make sure you refrigerate (not freeze) the body as breakdown of tissue happens very quickly in birds.

[janetafloat]

That's really sad, I'm sorry you had to find her like that

[friend2parrots]

I am so so sorry to hear of your birds passing. May your memories of her comfort you.

[EleriDragonfly]

Thank you all for your kind words.
I've put her in a ziplock bag and put her in the fridge, I just hope my sister doesn't find her she might not understand. I just hope my vet can help find out what happened to her, there are no avian vets close enough to my area. Though I've taken Wheatley to them a few times and they've always given him what he needed.

[Eurycerus]

I am so sorry to hear about your loss :[ I'd be so distraught! Cuddle up with Wheatley.

[marie83]

I'm so sorry to hear of your loss.

[Strawfrawg]

I'm very sorry to hear about your bird. The suddenness of it must have been a shock.