New Zealand citizens, particularly young professionals and graduates, are leaving the country in record numbers. Most are heading across the Tasman Sea – known colloquially as "the ditch" - to Australia, lured by better job opportunities and higher wages. However, immigration is also at an all-time high, with migrant arrivals from India the largest group, followed by the Philippines and China. Ruth Evans reports on what lies behind this Kiwi 'brain drain', and asks what the rapidly changing demographics mean for the country's future.