Tags and other distant-recognition markers for birds

Abstract

Marking birds for recognition at a distance poses special problems due to small body size, delicate plumage and the possibility of affecting flight. In many species, colours and plumage features are important in recognition and display, which may be disrupted by additional markers. Tarsal ringing (Spencer, chapter 5) has been used very successfully for many years on large numbers of birds, and other marking methods should be considered only when research would be unduly hampered by the limitations of ringing. The chief drawback of tarsal marking is that the legs of many species are hidden for much of the time---when they are swimming, in long vegetation, or in flight---and this has led to attempts to mark birds higher on the body. This chapter reviews the main methods used, concentrating on factors affecting the choice of the best marker for a particular study, and dealing with the materials used, the means of attachment, visibility, durability and any reported effects of the marker on the bird. Only a few key references to each method are given, since a recent bibliography (Marion and Shamis, 1977) lists the species on which each marker has been used and gives an exhaustive list of papers which can be consulted for details of the construction of markers and the techniques for attachment.