Remove birthday list in tasks

I don’t need a birthday list. It’s not cool. How may I remove it?

Due to the fact that a CalDAV calendar is used to store tasks too, you cannot remove the birthday calendar from the task list. An open issue already exists for it.

possible workaround:

do not enable/disable birthday-calendar in your admin-settings.
setup your own birthday-calendar and put all your birthday-dates in there.
they won’t show up in other calendars.
plus: setup an own calendar for tasks… or vice versa… don’t add your calendar-dates to your personal calendar but in a separate one.