I Found a Dead Bird: The Kid's Guide to the Cycle of Life and Death by Jan Thornhill

From chapters.ca:
The death of a bird is the jumping- off point for this intelligent, wide-ranging look at the cycle of life. From life spans to how things die, from what happens after death to how people cope with the loss of a loved one, Jan Thornhill guides young readers through difficult territory with grace, sensitivity, and touches of humour. She tackles the subject head on, never shirking from reality, but with a life- affirming perspective that connects death to the world around us as part of the natural, never- ending cycle of life. The book's lively design and colour photographs reinforce Thornhill's pragmatic, positive tone.