I know how to parallax scroll. No really, I'm not just putting that there 'cause you requested it be part of the proposal.
Get me the assets for your bird and (optionally) any image you prefer for the background (if you don't provide a background, I'll probably just wing it with some lame clouds or something) and I'll put together the javascript to get everything you listed working (background scrolling, bird flying, bird stopping, text dropping, the whole nine yards).
I'll code an html page, complete with the necessary Javascript (likely using JQuery) and deliver it within a day of being selected (likely within a couple hours).
Best regards,
Kris