Echinoderms

two fish. In the wild, kittiwakes have to learn to look for particular colours and patterns in the ocean to find the best place to fish. The researchers tried to recreate this for the captive birds by making them search for their food among a chequerboard of different coloured bowls. Chicks on the unrestricted fatty diet quickly learned which bowls contained food, but chicks on lean rations were very slow learners and never really worked out the colours and patterns associated with the food. “The ability of kittiwakes to associate the colour of a dish with the presence of food decreased proportionally with the magnitude of nutritional stress they had experienced during development,” the team write in the paper in the Proceedings of the Royal Society (published online). A climate shift in the north Pacific and Bering Sea in the mid-1970s resulted in fewer lipid-rich fish around the islands. By the early 1980s redlegged kittiwake populations on the islands had fallen by 50 per cent. “The results of our study suggest that declines in availability of lipid-rich fish — caused by climate change or human-induced — are likely to result in an inferior quality of seabirds in later life and an increased chance of mortality,” the team write. Previous studies have shown that passerine birds such as blackbird and sparrow appear to struggle to learn their mating songs if they do not have a good diet as a chick. A healthy diet looks vital — what is not clear is how much climate change and human interference is likely to impact on the preferred food of seabird populations. Many coastlines could be heading for a collapse in seabird numbers in the face of breeding failure or the fledging of disadvantaged chicks. Current Biology Vol 15 No 23 R944