Stewart’s passion has always been birds, and he has been involved in various studies in Iberia and beyond. He is a published wildlife photographer, member of the Royal Photographic Society; his photographs have appeared in various books and magazines. He has been involved with the excavation at Gorham’s Cave Complex since he was a child. He is currently reading for a PhD at Anglia Ruskin University, specifically looking at the relationship between Neanderthals and birds. Stewart is also working on birds as climate indicators. He heads the Natural History department at the Gibraltar Museum.