LinkedIn Birthdays in Hotmail Calendar

I coected my LinkedIn profile with my Hotmail account (a decision I will rue rest of my life) and it resulted in all of my LinkedIn contacts birthdays being stored to my Outlook Calendar. Whenever I try to delete those birthdays from calendar, it doesn't let me even edit it. It's quite agonizing as I don't want these birthdays on my calendar.

Can anyone help me there? Thanks!