Only users who are authorized, can close or delete squawks. Check on the User Authorization page under the sub-menu "Squawks" to see if you are authorized.
Closing a squawk: This should be done when a squawk has been taken care of. Once the squawk is closed, it will be moved down to the "Closed Squawks" section of the Squawks page. Once closed, no more comments can be added to that squawk, nor can it be deleted. The purpose of closing a squawk is to retain squawk history.
Deleting a squawk: Even though it is recommended to retain squawk history, squawks can be deleted. When they are deleted, you will not be able to access that squawk anymore.