Bird flight cycle

I love birds and flight, and last year I started a mini project that was based around bird flight, however due to lack of planning and the fact that I tried to animate it in a 3d program that I couldn't use very well it never really went anywhere, however I did find this:

http://www.brendanbody.co.uk/flight_tutorial/index.html

this is an incredibly helpful site on bird flight, going into great detail about different types of flight, the shape and pattern of flight, it was quite helpful when I read it before so now I am going to use it again to try and make a 2d flight cycle...hand drawn in photoshop