Open the App menu (select the right most icon on the bottom of the screen shaped like a square with a box around it).
In the All apps section find Calendar
Hold the icon down until a menu appears and select Add to Home
Position the icon wherever you want it on the Home screen
Click th Calendar icon on your home and that loads the Calendar app
Click on the icon in the upper left corner of the Calendar app (it has a little down pointing triangle under it)
Select Month
Select the Home button at the bottom of the screen
Now every time you load the Calender app it will open in the Month format.
When you reload the Bionic it will set the starting display option for the Calendar to whatever it was set to just before the reload.
... Thom