While there is still a lot to learn about how long birds live in the wild, one thing is clear: Many birds live much longer than we might expect.
Life expectancy in the animal world generally correlates with metabolic rate. In mammals, this is often linked to body size: Big mammals with slower metabolisms generally live longer lives; small ones with faster metabolisms live shorter lives. Humans, for example, live longer than dogs and cats, which live longer than mice and hamsters. (As is often the case with these generalized patterns, there are exceptions.)
Many birds are small and have extremely high metabolic rates. So, we would expect birds to be relatively short-lived. But they aren’t.
On the contrary, many birds live an extraordinarily long time, particularly when compared to similar-sized mammals. For example, under ideal conditions in captivity, a House Mouse can live four years. Meanwhile, a Broad-billed Hummingbird (a quarter the size of the mouse) can live up to 14 years in the wild.
Barn Swallows have been recorded living 16 years, enough time for these prodigious travelers to have traveled roughly half the distance to the moon during their annual migrations. European Goldfinches can live up to 27 years. Common Ravens are known to have lived 69 years, more than twice as long as the oldest-known dog.
As with their lack of physical aging, we are also still learning how birds are able to live so long with their super-fast metabolisms. The answers may offer clues to understanding aging in our own species.
One important point to keep in mind: Just because birds can live a long time doesn’t necessarily mean that all individuals of the species do live that long. Similar to us humans (who have been recorded living to 122), most individuals will have shorter lives than those at the extreme.