* I guess that there is no inbuilt way in Outlook 2007 to NOT display the "Birthdays" specified in Contacts, since by any means they would be considered as an Event for Outlook Calendar
* So the best way would be either not to enter the Birthdays in Contacts or else if you really need them to be there, you can opt for deleting those entries from Calendar itself.
* Below are the steps to achieve this:
1) In Outlook, select the Calendar option
2) Then go to the View menu, within that Current View and from there select "Events". This would show you all the calendar entries in a tabular form
3) Then from there they should be group by recurrence and then look for the "yearly" group.
4) You can then select all the birthdays and delete them. That way it goes from the calendar but remains in the contacts.
Hope this helps (^_^)