Birthdays migrate to Profile2
I might be wrong but I believe (most) dates in Drupal are simply stored as 11 digit integers. The format you refer to is only whats displayed on the page. Your migration probably just needs to be moving the integer date data by simply moving the data from your source csv column into your new profile2 Drupal Field:

$this-&gt;addFieldMapping('csv_birthday_column', 'new_profile2_birthday_field');


Then you just use a Profile2 Manage Display under the Field UI to setup how you want it to look on the page such as d/m/Y.

EDIT:

If your CSV has for example "04/15/2013" as a date for a piece of content you could use PHP strtotime() in a Migration class prepareRow() function to get an integer value to save in Drupal.