Geographic-Variation in Zebra Finch Subspecies

Abstract

Geographic variation in the Zebra Finch Taeniopygia guttata was examined by comparing live wild-caught and captive T. g. guttata from the Lesser Sunda Islands in Indonesia and T. g. castanotis from the Australian mainland and confirmed by museum skin measurements of guttata and castanotis. (1) T. g. castanotis is significantly larger than T. g. guttata, as measured by wing length, weight and bill length. (2) castanotis have redder, darker, brighter bills than T. g. guttata. (3) T. g. castanotis males have larger breast- bands than T. g. guttata males, even when the size difference is taken into account, with strongly pronounced black bar- ring on the throat and upper breast which are absent from T. g. guttata males on Lombok, Sumbawa, Flores and Timor. (4) T. g. castanotis produce lower frequency distance calls and the males differ from T. g. guttata males in having a noise part to this call. (5) The songs of captive T. g. castanotis males are lower in frequency and their song phrases are shorter, with fewer elements per phrase, than captive T. g. guttata males from Timor. In contrast to the differences between T. g. castanotis and T. g. guttata, little geographic variation was found within T. g. guttata on the four islands studied, although there was a cline of decreasing size in bill depth from west (Lombok) to east (Timor). The status of the two forms, T. g. guttata and T. g. castanotis, is discussed.