My friend Peter, a bird enthusiast, found a dead petrel on Stewart Island off the southern tip of New Zealand. Petrels fly the southern oceans, circumnavigating the globe, stopping occasionally to lay an egg, and bring up a youngster before returning to the oceans.The bird had a ring, which he carefully extracted and sent back to the appropriate record keeping centre. Three months later, his parents (also bird enthusiasts) were attending the sherry party reception for a specialist birders weekend in Aberdeen and met a man who dedicated himself to bird ringing.