This is an easy one.
If you’re using the website: just go to Site Preferences by clicking the cog icon in the upper right corner. You’ll see several checkboxes, including an option to turn off appearing in the birthday list.
If you’re using the Grokio Communities app: Click on the bottom right tab, called “Me” and navigate down the list to the section called “Settings”. Clicking on it will show several toggle options, one of them being “Appear in Birthday List”, which you can deactivate.
Hope this helps,
The Grokio Support Team