diff --git a/modules/birthdays/birthdays_birthday.inc b/modules/birthdays/birthdays_birthday.inc
index d2668cf..cf76658 100644
--- a/modules/birthdays/birthdays_birthday.inc
+++ b/modules/birthdays/birthdays_birthday.inc
@@ -53,6 +53,7 @@ class BirthdaysBirthday {
       return self::fromEmpty();
     }
 
+    $mask = str_replace(array('dd', 'mm', 'yy', 'yyyy'), array('d', 'm', 'Y', 'Y'), $mask);
     $result = date_parse_from_format($mask, $text);
     if (!empty($result['errors']) && empty($result['day']) && empty($result['month'])) {
       throw new InvalidArgumentException(t("That is not a valid birthday."));