The flight and feeding customs of the most important sea bird species of the Galapagos Islands are described. Some characteristic body and wing measurements are used to describe the flight of these species. The species which are able to forage furthest out at sea and deepest in the water are the most successfull on the Galapagos Islands, measured by their abundance. The least abundant bird is the lava-gull, a shore bird and surface-feeder.