If you’ve already created an account with your email address, you can also merge it with a third party login option (Google/Facebook/Apple ID), From then on, you can simply log in through Facebook or Google or Apple ID. Simply follow the steps in the app:
Please note that if you logged in with a third party login option from the start, you cannot create a separate Birdbuddy account with the same email address you’re using for that service. (You will encounter the following error: "You used this email to sign in with Google/Facebook/Apple ID. Welcome back! Please sign in using that method again.")