You could also say:
My lovely bird
Do not leave me alone
Because I have no friend but you
(OR)
My dear bird
Don't leave me lonely
Because you're my only friend
And you know what? You could go for ages suggesting translations for that piece and no one can ever say it's wrong as long as it conveys
the meaning.
But I'll tell you what I think.
When it comes for translation I do not like to
use the words right and wrong to talk about
the translated text as long as it conveys the
meaning.
I'd rather use the words:
Good, better and best.
Why? here we come to the next point that translation is an art. It's the art of writting someone else's ideas in your own words. But not simply that, you should be careful to the type of writing you're producing be it poetry or prose comedy or tragedy...etc. all that in additin to the meaning of the text.
And I believe, even if the original text didn't seem good enough in order to be translated beautifully then you should stir, I do not know if it's right to say that, but you should stir your imagination a bit.
And that's what I tried to do.
Thanx for suggesting the other translation and thanx for taking the time to read my message.