Daily and seasonal activity patterns of partially migratory and nonmigratory subspecies of the Australian silvereye, Zosterops lateralis, in captivity

Abstract

We recorded the locomotor activity of the partially migratory Tasmanian silvereye, Zosterops l. lateralis, and the nonmigratory mainland silvereye, Z. l. familiaris, continuously over 17 and 15 months, respectively, to identify daily and seasonal patterns. While graphing the data showed several trends, statistical analysis did not reveal a significant difference between subspecies, making this study mainly descriptive in nature. The lack of statistical differentiation was possibly due to the low number of study animals and similarities between them. During the first year in captivity, the Tasmanian birds displayed heightened activity during the migratory periods, which was most likely migratory restlessness. The Tasmanian birds did not show any nocturnal activity as in previous laboratory and field studies, rather their activity patterns were similar to those of diurnal migrants, possibly reflecting the temporally variable nature of their migration. Although the Tasmanian birds displayed higher overall activity levels than the mainland birds during the first year in captivity, the activity patterns were similar between the subspecies. Captivity appeared to influence the activity of both subspecies in the second year of the study; following the onset of molt, neither subspecies regained the activity levels of the previous year, nor did activity follow the same pattern. Possible reasons (e.g., prevention of breeding) for this are discussed. This is the most detailed study to date on the daily and seasonal activity patterns of an Australian bird in captivity.

Mosquito Communities and Avian Malaria Prevalence in Silvereyes (Zosterops lateralis) Within Forest Edge and Interior Habitats in a New Zealand Regional Park

“…Second, we cannot exclude the possibility that birds were being infected while roosting in a different area from which they were captured. However, silvereye home ranges averaged less than 300 m for the majority of individuals on Heron Island (Australia) (Catterall et al 1989), and resident silvereyes rarely move at night during the breeding season (Chan 1995;Funnell and Munro 2010). In addition, all eleven of our recaptures occurred within-site in Waharau.…”