Taken from Bloomsbury Web Chat 30th July 2007
This answer comes from J K Rowling when asked about the death of Hedwig:
Twinkletoes: Why did you feel that Hedwig's death was necessary?
J.K....
Its not the duel its the battle of Hogwarts and these are the people who die :snape , fred , lupin , tonks , voldermort , bellatrix , nagini , harry ( only for a few minutes then comes back ) , goyle...