The likelihood of seeing the same bird in your garden does of course exist, but as time goes on the chances of it being exactly the same feathered friend do diminish, and maybe quicker than we would have hoped. The majority of the birds we see at feeders will be the songbirds, with a few larger ones like woodpeckers, cardinals or jays thrown in for good measure. The general rule is that the smaller the bird, the shorter its lifespan. Garden or songbirds are usually quite small, giving them an average of around 2 to 5 years of mortality. Going up the size scale, we’ve found that the average age of hawks is 8 to 20 years, eagles 20 – 25 years, seabirds can be from 30 – 50 years. But this “rule” isn’t always the case – warblers, for example, being often much smaller than your average songbird, has an average of 3 – 6 years, and hummingbirds average 9 years. However, the maximum lifespan recorded for many of these birds has been much higher: the average age of a blue tit is said to be 2.7 years, but the oldest recorded so far was over 21 years old.

The general rule is that the smaller the bird, the shorter its lifespan.

How do we know?

The above figures are based on information that has been learnt from gathering data on specific birds. As far as we know, birds don’t sing Happy Birthday to each other with a cake with x number of candles on it, so the only effective method in place is to fit a band or ring inscribed with a unique serial number onto the bird’s leg, or attach a tiny transmitter to the body. Ideally this is done soon after hatching, which carries its own risks of adults abandoning the nest, so more often than not the birds are caught by hanging up something called a mist net. This is a fine meshed net usually strung up between two poles or trees in a known high bird population area, and simply waiting for the poor things to try and fly through the space and instead get caught in the net. It is overall a harmlessmethod, although there must be some amount of stress for the captured bird, but the people licensed to carry this out are nothing short of saintly, and handle the birds carefully, quickly and efficiently, ensuring they are released as soon as possible. It only takes a few minutes to clip the ring or transmitter onto the bird’s leg or around the neck, and away they go. Over time, those nets will be erected again, and the rings on caught birds will be logged, and they will be released again. Devices like this were fitted in the past to mainly track migration but the data is also used to determine survival rates, which in turn can help us calculate the average bird age.

A life lived in the open

Of course, for this to be fully effective then the birds need to be followed throughout their lives from hatching to death, which is obviously not an easy thing to do, so the data that has been amassed over the years, whilst still impressive, can never give a full picture. The most common bird species are “easier” to catch simply by their abundance, and larger species like seabirds or game birds can also be physically easier to catch than smaller ones, but nonetheless it is hard to get precise information. Bird plumage can give a slight indication as to what stage in maturity a bird is, but after the juvenile feathers have moulted and adult plumage comes through, this stays the same for the rest of the bird’s life; no greying hair, walking sticks or varifocals to be seen.

A songbird in the wild has about a 25% chance of making it to its first birthday.

This is why the medianage of a bird’s species, such as the age quoted above for hawks, can be so wide. Add in the fact that some of each species have been found to live extraordinarily long lives, the “average” soon becomes the “possible”. Scientists would need to ring the majority of the population of every species and then capture them all again at a later date to know for sure, and of course that’s just not going to happen.

To understand how long a particular bird species lives, it is first necessary to understand the factors that can affect the mortality of that species. It is a globally accepted fact that, of all birds hatched, there is a high mortality rate before the birds have even left the nest, or fledged. A songbird in the wild has about a 25% chance of making it to its first birthday, and then after that, less than a 50% chance of surviving more than two years, with some scientists estimating the chances of a bird dying before full maturity can be as high as 80 – 90%. It’s fairly safe to say that most birds never die of old age. Birds lead difficultlives, and they are more likely to be killed by predators, experience fatal accidents, catch life-shortening diseases or succumb to winter starvation, than spend retirement chilling out in a comfy tree hole somewhere surrounded by loved ones. However, these harsh facts serve to maintain an unknowable balance – considering that most bird species will raise multiple broods in one breeding season, potentially bringing forth around 15-20 birds per pair each year, were these mortal factors not to come into play, the world would soon suffer a stifling overpopulation of birds, bringing a whole new set of issues.

Ages and cages

Unsurprisingly, bird life spans have been seen to increase greatly in captivity, for the simple fact that they don’t undergo many of the risks of the great outdoors. They will never lack food, should be free of predators, and often any diseases or accidents involving harm or injury will be soon attended to. This could therefore be said to create a false scenario, with reports of house sparrows and cardinals living to their mid-20s adding little to the data sets. But, the existence of records that show the converse, such as the wild starling having lived for 3 years longer than the oldest recorded captive starling, alongside the fact that not all species of bird adapt well to captivity with some species showing shorter life spans than their wild counterparts, means that these situations can be integrated into the overall calculations. Like all animals, us included, the average age of a species will always be influenced by an infinite number of factors.

Parrots are the only birds that can live longer than humans.

As mentioned, it can be broadly stated that the bigger the bird, the older it is likely to get. Parrots, albatrosses and eagles can all live well into their fifties, all being well. In fact, parrots are the only birds that can live longer than humans, with some types pushing a life expectancy of 100 years. The oldest known parrot is alleged to be a blue and yellow macaw called Charlie, previously owned by Winston Churchill, that made it to at least 104 by the year 2004, although Churchill’s daughter has since said she only remembers him having a grey parrot called Polly.

More recently and believably is the wonderful tale of Wisdom, a female Laysan albatross who lives in the wild and returns each breeding season to one of the most important albatross breeding grounds in the world, the Midway Atoll Wildlife Reserve in the North Pacific. She belonged to a clutch hatched in captivity in 1951, was tagged in 1956 and released to the wild, where she has returned for breeding ever since. Albatrosses lay on average one egg every year, and Wisdom is believed to have produced around 36 eggs so far. Clocking up around three million miles over her impressive 69 years, she recently returned to her nest in December 2020 and, with the same mate she has had since 2006, has laid another egg.

So – is that Tommy the Great Tit at the feeder again this spring? In truth, probably not. But there’s no harm thinking it could be.