A comparison of annual patterns of behaviour and physiology between partially migratory and non-migratory subspecies of the Australian silvereye zosterops lateralis, in captivity
- Publication Type:
- Thesis
- Issue Date:
- 2007
Closed Access
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01Front.pdf | contents and abstract | 758.19 kB | |||
02Whole.pdf | thesis | 15.81 MB |
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NO FULL TEXT AVAILABLE. Access is restricted indefinitely. ----- This study recorded and compared the behaviour and physiology of the partially migratory
Tasmanian subspecies, Zosterops lateralis lateralis, and the sedentary mainland
subspecies, Zosterops lateralis familiaris, of the Australian silvereye over an extended
period in captivity. Tasmanian birds were held in captivity for a total of 17.5 months, while
the mainland birds were kept for 13 or 16 months, dependent on date of capture. During
this time orientation behaviour, locomotor activity, fat deposition, body weight, food
consumption and moult of each subspecies were recorded. The Tasmanian birds
displayed significant seasonally appropriate orientation during each of the three migratory
periods and also during the breeding and moult period. In contrast, the mainland birds did
not display significant orientation at any time. Graphing of the locomotor activity revealed
several trends in the daily and annual activity patterns of each subspecies. During the first
year in captivity the Tasmanian birds exhibited elevated activity levels during the migratory
periods, which is most likely due to migratory restlessness and their activity patterns were
similar to those of diurnal migrants. The Tasmanian birds were significantly fatter and
heavier than the mainland birds and during the first year in captivity; the Tasmanian birds
displayed increased fat deposition during the migratory periods and the overwintering
period. During the second year in captivity, after moult, both subspecies failed to develop
the levels of activity recorded during the previous year and also weighed significantly less.
This was especially apparent during the second autumn migration period. During this time
the Tasmanian birds also failed to gain the fat levels of the previous year. Captivity
appeared to affect both subspecies and influenced the development of migratory activity
and fat deposition in the Tasmanian birds. Both subspecies showed similar levels and
patterns of consumption of nectar, apple and a protein-mix and nectar consumption had a
significant inverse relationship with temperature. The subspecies differed in their
consumption of mealworms, with the Tasmanian birds consuming mealworms, in higher
numbers and with greater frequency than the mainland birds. Both subspecies moulted at
the same time as wild birds. The Tasmanian birds commenced and completed moult
earlier than the mainland birds and exhibited less variation between individuals. Overall
the differences between the subspecies were consistent with their differing lifestyles and
the adaptation of the behaviour and physiology of Tasmanian silvereyes to their migratory
habit.
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