Cause
Like all animal phobias, ornithophobia is commonly caused by a negative encounter with the feared animal. Many birds can be somewhat aggressive in hunting for food, and childhood run-ins with pigeons or seagulls bent on stealing snacks are common. Many people, whether or not they have a full-blown phobia, are wary of snacking in areas with large bird populations. Birds sometimes fly through open windows or down chimneys, causing an uproar in the home. If the sufferer was nervous in such encounters, this could be enough to trigger a phobia.
Read more about this topic: Ornithophobia