From Opus

If you know the email address you registered with and can still receive email at that address, go to 'Forgotten Your Password page' and fill in that email address. You will be sent your user name and instructions for resetting your password. If you are sure of your email address but get "The email address you entered is not in our database" it means there is no Birdforum account with that email address. Either you used a different email address for your Birdforum account or you have us confused with another Birding related forum site.

After you reset your password, you can use the 'Edit Email & Password page' to change your password to one you can remember. You can change your account's email address there as well.

If you have forgotten your password and either forgotten your registration email address or can no longer receive email at that email address, 'Contact Us' for assistance. Tell us your forum user name, current email address, and any other information you remember about your Birdforum account so we can look up your account.

Since passwords are encrypted, there is no way to resend your original password. You may need to check your spam filters and folder if you do not see any email within a few minutes.