From Opus

There is normally no need to cancel a Birdforum account. If you expect not to need to post at Birdforum, you can simply stop visiting our site. There is nothing you need us to do. Under our Privacy Policy, we won't email you or release your contact information. Inactive accounts are of little consequence. The advantage is that if you change your mind, perhaps because you have a Bird related question, you can return to Birdforum, log in, and post.

For additional privacy, you are welcome to remove the information in your 'Edit Profile Page' (Instant Messaging names, Location, etc.) since this information is visible to the public for both active and inactive Birdforum accounts.

If you have subscribed to any forums or threads, have asked for email notifications, and are no longer interested in receiving those messages, delete the subscriptions on your 'Forum Subscription Page'