Effects of Band Color on Survivorship, Body Condition and Reproductive Effort of Free-Living Australian Zebra Finches

In domesticated laboratory Zebra Finches (Taeniopygia guttata), leg bands of certain colors affect mate selection, parental effort, reproductive success, sex ratio of offspring, and survivorship. I tested the effects of these same colors on survivorship, body condition and reproductive effort of free-living Zebra Finches over several breeding seasons at two colonies in northern Victoria, Australia. At the "Cloverlea" colony, adults of each sex received either "attractive" or "unattractive" color bands. Nevertheless, survivorship to 12 months was not affected by band color nor was there compelling evidence (mass, bill color and molt) for deteriorating body condition due to reproductive costs; there were no sex differences in survivorship. Reproductive effort each breeding season in these free-living birds may not be as great as that in some laboratory populations because in nature the season is shorter and the interval for recovery correspondingly longer. In contrast, at the "Danaher" colony, where birds had unique color combinations of three bands (plus one metal band), a retrospective analysis of four years of data showed that there were significant effects of band color on reproductive effort of females; they laid more eggs if mated to males having a single red band (attractive color) in their combination than if mated to males having a single light-green band (unattractive color) or bands of other colors (neutral attractiveness). They laid an extra clutch, but this did not result in significantly more fledglings and independent young being raised by the pair. There were no band-color or sex effects on survivorship of adults at this colony. There were no obvious biases in the allocation of band colors or identification of breeding pairs that might explain the extra-clutch effect. The finding on red-banded males is largely consistent with that described for domesticated Zebra Finches, where females make a differential reproductive allocation in response to their partner's band color. No similar effects were found for female band color where, contrary to expectation, females with black (attractive) bands had significantly fewer fledglings than did females with color bands of neutral attractiveness. The overall conclusion is that color bands do not significantly affect the behavior of wild Zebra Finches, but it would be wise to omit red bands on males where possible.