Lifespans.

["Greg & Val Clancy" <>]

Dave is certainly correct with respect to this issue.  I have been banding 
birds since 1971 and at that time it was thought that small birds would 
expire at about 5 years of age due to their high metabolic rates.  When I 
retrapped a White-browed Scrubwren at about 18 years of age I realised that 
our preconceived ideas about aging in birds needed to be reviewed. 
Certainly not all birds will reach the maximum age but many small passerines 
are now showing that an expected five year lifespan was too pessimistic.
Most maximum ages attained by birds are limited by the time span of the 
particular studies that have been carried out to date.  Over time these 
maximum ages are likely to increase, especially for larger birds.

Greg Clancy