People who haven't had a pet become a part of their lives probably won't get this; people who have had a pet bird long enough to really gain the creature's trust will understand.
Casper the bird was my little buddy. For the last 10 years as I struggled with post traumatic stress disorder and heart disease, he was my constant companion, always cheerful, happy to see me, a little speck of light. He would always whistle a greeting when I entered the room, he'd mimic my laugh (just to tease me, I swear); we'd carry on lengthy whistled conversations (I never knew what about, but he'd get pretty excited); whenever I went over to his (quite roomy) cage he'd fly to the front and hang on the bars with his head cocked to the side, chittering away. He'd chirp his head off in the morning till I brought him in my office or just gave up and went into the living room and hung out with him there.
He'd been getting increasingly feeble (he was 10, after all, about twice the average life expectancy for a budgie). His attitude never changed, but he'd sleep more and more in between spells of activity. Then suddenly yesterday morning he was very sick, and by noon he was dead.
So hoist a beer to the little blue bird tonight. He was a good soul, and my house will be a quieter and sadder place from now on.