I really have a hard time believing that they used a GoPro. It's probably the least aerodynamic camera around - you might as well strap a brick to the bird. I doubt the bird would even try to fly with such a thing strapped to it.
Almost any other action cam would be a better choice. Personally I use an 808 #16 for small things like this, or strapping to rockets and planes and such, but there are other good choices as well.