How long do birds live?

Surprisingly, this simple question is quite a difficult one to answer. Ornithologists usually ring or band the birds in the wild and collect them again using mistnets. Using the data they gather over a period of time, they try to estimate the life-span of the birds. This sort of bird life estimation studies have only been carried out in the last thirty years and it has been observed that some sea birds have survived throughout so their life spans are yet to be estimated.

From the data gathered so far, it appears that that the average life span is far lesser than the maximum life span of any one bird. for example, Robins have an average life span of 1.1 years but few birds have survived up to 20 years in the wild. Very few birds actually die of old age and a vast majority of the birds perish during the first few days of their lives.

In general, it has been observed that larger birds have longer lives compared to smaller ones. The birds living in tropics live longer compared to the birds living in temperate zones. It has also been observed that sea birds in general live longer than land living birds. Birds kept in captivity are also observed to have a longer life span compared to birds living in the wild. These generalisations are ofcourse are not without exceptions.


Reference:
Bird Life Expectancy: http://twootz.com/article/Bird-Life-Expectancy
Life span of birds: http://www.countrysideinfo.co.uk/bird_lifespan.htm
How long can birds live: http://www.stanford.edu/group/stanfordbirds/text/essays/How_Long.html