Among British birdwatchers, A Rocha is best known for Cruzinha, its Portuguese centre, where we began tape-luring European Storm-petrels Hydrobates pelagicus in 1990. The original aim was simply to discover whether non-breeders passed the Algarve coast. Since then, over 6,000 have been caught, measured and released. A Rocha now works in partnership with Cardiff University to investigate responses to climate change in migration patterns. Faecal and vomit samples are used to identify prey species using molecular techniques, and by linking this dietary information with year-to-year changes in sea temperature, plankton productivity and the birds’ energy levels, we are building an increasingly detailed picture of how climate change is affecting marine ecosystems. Twenty-seven years ago, we had no idea that it would develop into such a complex and rewarding study!