Diurnal pattern of mass in an urban Marlborough population of silvereyes (Zosterops lateralis)
|Title||Diurnal pattern of mass in an urban Marlborough population of silvereyes (Zosterops lateralis)|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Bell, M, Bell, C|
|Type of Article||Full article|
|Keywords||Diurnal weight change, mass-dependent starvation risk, silvereye, Zosterops lateralis|
Silvereyes (Zosterops lateralis) in an urban population in Marlborough, New Zealand showed considerable diurnal changes in body mass. At first light, average mass was 12.39 g, rising to 13.91 g by dusk. This represented a 12% average loss of mass overnight. The overall average mass was 13.22 g; birds were 6% below average at 0700 h, but increased rapidly to be near the average for most of the day, rising significantly in the 2 hours before dusk (1700 h). This pattern of diurnal mass change is consistent with theoretical models suggesting that birds should manipulate daily mass gain in order to trade-off starvation risk with mass-dependent predation risk.