Complex sentence: Bird was born in Guildford, Surrey in the United Kingdom into a "solidly professional middle-class" family as the third of four children of Heather (née Gage) and Graham Bird, both of whom are economics professors at the University of Surrey.
Split into simpler sentences: Bird was born in Guildford, Surrey, England, one of four children of Heather (née Gage) and Graham Bird. He comes from a "solidly professional middle-class" family; his parents are Economics professors at the University of Surrey.