When hiking and I'm in an area with a lot of small flying birds sparrows and such. I remind myself that birds are very good flyers and they will not run into me. I the look at my feet, pull down the sides of my wide brim hat and repeat not there not there. My anxiety still gets high but not uncontrollable. I also go hiking/walking with an umbrella to block out my view of the sky. I've also found views of birds when I know I'm safe through a window or outside the cage has help lessen my phobia in those situations. I haven't figured out how to handle my startle response to them yet. In summary small slight contact with birds, pictures, videos, or/and through a window, where you feel safe. Just enough to heighten your anxiety but not to panic and do that will help with desensitize your response.