The Duck in the Park by Hilary McKay
This is a wonderful new character from an award-winning author. Lulu loves animals. She can't understand people who don't like them - people like her teacher, Mrs Holiday. When Lulu tries to help Mrs Holiday to find her perfect pet, she is banned from bringing an animal to school ever again! Then Lulu rescues an abandoned duck egg. She's going to have to take it to school to keep it safe. She's not really breaking the rules because it's just an egg. Nothing bad can happen, can it?