From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040115

Description of problem:
The birthday to calendar mapping function should be abstracted to be
independent of year (as birthdays occur on the same date every year).

Version-Release number of selected component (if applicable):
evolution-1.5.3-1

How reproducible:
Always

Steps to Reproduce:
1.Enter birthday in contact entry
2.Birthday mapped to calendar, but only for current year.
3.Birthdays in other years not displayed
    

Actual Results:  Birthdays are only displayed for one year.

Expected Results:  Birthdays would be displayed on the appropriate
date every year.

Additional info:

This is a really nice feature and I realize that its inclusion was due
to a bounty. So, I am not holding my breath that this will ever get fixed.