I noticed that if you hold the fly button it consumes the energy faster, but for some reason it happens only on the browser, didn't have time to fix it before the deadline.
About the collisions, it was hard to design it using the small screen resolution, in this case removing 1 or 2 pixels from the collider may affect the behavior of the eagle in many ways. If the screen was bigger, there was much more space for user friendly colliders :)