I too have a few irrational fears I am combatting. One method I use may work well in this case:
Print or write out on a piece of paper the thought you want to get across to the amygdala - the fear center of the brain. The amygdala is very fast at sending messages to the rest of the brain when it's triggered, but can only receive messages slowly, and when it's not in a paniced state. (From what I've read.. I'm not a neurologist.) So print out on a piece of paper the message you want to send to the amygdala. Something simple like "My fear of birds is irrational. Birds do not equal danger." Use big text and bold colors. Place this peice of paper someplace you spend a lot of time, such as next to your computer. Each time you set down at your desk, get into a habit of reading this paper. Over time, your amygdala will get the message.
Interestingly, the watchtower employs a similar strategy of bombarding the brain with their message 3 or more times a week. Becasuse watchtower thinking is repeated so frequently, and so emotionally (condemnation, guilt, punishment) - they can very successfully emplant neural associations to trigger sometimes without our even realizing it.
It took a while for your brain to learn the watchtower pattern, so give your brain adaquate time and training to relearn out of it.
- Lime