Hi Mayy,
I've noticed this phenomena as well. Perhaps the birds are playing...chicken?
The only real "problem" I've had with bird encounters is with red-winged blackbirds, especially in nesting season. They prefer hedgerows alongside the roads, and are very territorial. "Territorial" means aggressive in this case, and they will swoop down and tap one -- hard -- on the helmet. I know some local cyclists have had their helmet shells cracked in similar attacks, and the birds have sometimes fluttered right in front of my face. About all one can do is proceed (faster!) through their territory.
I've come to think of them as a training aid.
Best,
Dan.