Bird bone assemblages from coastal sites in the north and west of Scotland are very diverse. Here, bird bones from 25 assemblages from 15 sites are compared. Many birds were caught for food, but there are also up to 50 incidental species, some of which are represented by one or two bones only. While the principal origin of the birds is seabird fowling, some were also obtained as a bycatch of fishing and others were collected casually. Some may have been collected accidentally with seaweed. Many are non-anthropogenic, from raptor discards and bird pellets, but possibly also from other predators. These diverse origins of the bird bones have important implications for interpreting former avian distributions. Copyright © 2014 John Wiley & Sons, Ltd.