Consider the following situation: Over the last 2 to 3 years, all the world's birds and bats outside of those in human captivity or domestication have stopped getting sick; sick - even terminally sick - animals have recovered, and these animals now have lifespans extended to about double that which they formerly could have expected.

Should humans capture any of these birds or bats, their immunity ceases and their aging progresses as usual from the creature's apparent age. Any birds or bats released or escaped from human captivity and observation also quickly (re)acquire this newfound immunity and longevity.

Should a captured bird or bat be examined sufficiently closely soon after capture, scientists might notice trace quantities of Hafnium, Tantalum, Silver, Holmium and Lutetium above those normally found in birds, as well as subtle differences in bone layering, but no other explanation for their former immunities and longevity.

The agency by which this is achieved is an alien nanotechnology with sophisticated rod logic brains that have been instructed to covertly spy upon humans, and if any humans get too close, the nanotech will self-destruct without harming the animal (leaving behind the trace elements I mentioned, plus Carbon, Nitrogen, Oxygen and Hydrogen, none of which are likely to be detected). However, a side-effect of being covertly infiltrated by these alien general-purpose nanites is that the nanites will also implement unrevoked prior programming that instructs them to look after the health of whatever organism into which they are inserted. The nanites will avoid an uninfiltrated animal that humans are observing, but if they don't believe that any human is paying much attention - and the nanites are individually pretty smart and they all talk to one another, so there is a good chance that they'll know - they'll infiltrate that animal too. After all, if a canary escapes, humans would expect it to stay in the vicinity for a while.


Observation means that either a human or a human-made device physically restrains the animal, a human or a human device spends a significant amount of time watching the animal, such that another human would consider the first person or device to be watching that animal, (really watching it, as in "it is part of my research project" watching, not just casually observing it since it lives nearby) or a human or human-made device attaches an active tracking device.

Passive tracking devices such as leg bands do not count as ongoing observation. Any nanites present would self-destruct on capture of an animal, but after being banded or otherwise marked, if it appears that no great amount of attention is being directed toward the animal, then it will be re-infiltrated.

The nanites that are infiltrating the world's birds and bats are AI spies. They are individually as intelligent as a human, but have no sense of self-preservation. While their orders dictate that they must prevent discovery by humans, they must also observe humans while their host animals continue to act normally as far as possible. Since the act of observing humans leaves their hosts able to be observed by humans in turn, they cannot simply self-destruct any time a human looks at them sideways, since that would leave them unable to fulfil their mission. They are smart enough to know when a human is paying attention to their host with a view to capturing it, either now or potentially in the future, or is looking for any unusual behaviour or traits. Active tracking devices that rely upon GPS or RF broadcast and enable location of the animal at a distance are considered to be ongoing observation.

Since pretty much every non-domesticated bird or bat has been infiltrated, the loss of a few here or there if humans catch and active-tag some is acceptable, but if the opportunity for unobserved reinfiltration occurs, it will be taken.

If humans begin to capture birds or bats en-masse, the nanites will probably assist a few to escape. These animals aren't all that smart naturally, but they are smart enough to recognise a new "predator" eventually, so their fleeing wouldn't be considered unusual.

TL,DR: the nanites are each as smart as a human and they all talk to each other, and if they think that humans are too interested in an uninfiltrated potential host, they won't go there, and they'll self-destruct if humans appear to be approaching a position where there is any possibility that they could be discovered within that host by humans.

End Edit

However, would we even notice? If so, how long might it take? Could we notice in under 5 years?

Extra credit: Can anyone deduce why Hafnium, Tantalum, Silver, Holmium and Lutetium in addition to elements C, N, O & H and other light elements?

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    $\begingroup$ What happens to the cats who eat the birds? $\endgroup$
    – Mazel
    Apr 26, 2017 at 22:51
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    $\begingroup$ If human observation cancels this immunity and added longevity, then people, by definition, can never notice. $\endgroup$ Apr 26, 2017 at 22:53
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    $\begingroup$ @MontyWild Does it count as being held captive if a bird is tagged with a GPS tracker? $\endgroup$ Apr 27, 2017 at 1:24
  • 4
    $\begingroup$ Related: Would we notice if trees falling in the woods stopped making sounds? - really there might be something interesting in your question, but it is buried under too much noise. $\endgroup$ Apr 27, 2017 at 13:21
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    $\begingroup$ The most obvious sign of a bird’s health is its plumage. Especially this time of year in my neck of the woods, you can immediately tell which male cardinals are eating well by their brilliant reds—the lady cardinals can tell too. Good health doesn’t exactly equate to good eating, but the healthier the bird, the more time it can spend eating, and the better-looking it would be. $\endgroup$ Apr 27, 2017 at 16:18

12 Answers 12


Professional ornithologists and conservationists would definitely notice. They would probably realize that something is going on within a few years.

There is a large community of bird watchers, and a smaller community of professional ornithologists, such as the Cornell Lab of Ornithology. They have a citizen science program.

Each day, bird watchers report tens of thousands of bird observations to citizen-science projects at the Cornell Lab of Ornithology, contributing to the world’s most dynamic and powerful source of information on birds. . . . Scientists use these data to determine how birds are affected by habitat loss, pollution, and disease. They trace bird migration and document long-term changes in bird numbers continent wide.

These people are monitoring wild birds. They will notice.

AdaliaBooks brought up a good point in his answer; Deaths of small birds are not primarily caused by old age. Small birds get eaten before they die of old age. However, large birds are a different story. Nothing eats bald eagles. Bald eagles are a symbol of America, and get plenty of attention by wildlife monitoring scientists. We know the age at death of at least a few bald eagles, and we have noticed that, thanks to conservation efforts, they are living longer than they used to.

The second part of your question was, how long would it take for us to notice? If we just track bald eagle deaths, we would definitely notice when 50 year old bald eagles become routine, but that won't be for another couple decades. it will be at least 10 years before we notice that bald eagles are definitely getting suspiciously old. The Florida wildlife survey I linked, monitors the number of fledglings per active nest. Presumably this number would jump up if eagles stopped getting sick. They would spend less time and energy fighting diseases, and more on making eggs.

This doesn't mean that they would accept an explanation like alien nano-bots. I'm sure a proper biologist could spin a half dozen theories for super long lived birds that are less crazy than nano-bots. That being said, "less crazy than nano-bots," is not a very high bar.

  • $\begingroup$ Good point about birds of prey, they are far more likely to be noticed and effected by this. But I agree it would take a long time even then for a change to actually be noticeable. $\endgroup$ Apr 27, 2017 at 10:48
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    $\begingroup$ Maybe the increase in bald eagles' life spans is actually caused by OPs nanobots? That is to say, even if ornithologists recognised the increased life span, they might actually attribute it to human efforts, so the aliens would still go unnoticed (could even be an idea for a little side plot?) $\endgroup$
    – kratenko
    Apr 27, 2017 at 13:34
  • $\begingroup$ Edited to reflect your comments. $\endgroup$ Apr 27, 2017 at 14:32
  • $\begingroup$ "Any birds or bats released or escaped from human captivity and observation also quickly (re)acquire this newfound immunity and longevity." The OP isn't 100% clear, but seems to imply that observing birds in the wild means they don't get the longevity. $\endgroup$
    – industry7
    Apr 27, 2017 at 16:49
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    $\begingroup$ But if more animals of any kind survive, wouldn’t they eventually run out of food? $\endgroup$
    – Michael
    Apr 27, 2017 at 17:31

The cities would be the first to notice. And I mean really notice.


Welcome to my home city of Aberdeen on the north-east coast of Scotland, the 'oil capitol of Europe', which really should be better known for its seagulls. The local politicians have recently issued a warning over upcoming 'Seagull wars' expected by the city council as residents face a fresh round of battles with an oncoming storm of giant seagulls which have plagued the city since the dawn of time.

Seagulls are scary

I have seen them dive bomb numerous people in order to steal food out of their hands, intimidate pensioners, and terrorise children in play-parks. The birds have been caught on camera destroying property, harassing all kinds of residents, and even shoplifting... and not as a one-time news story either: it happens year after year after year.

The city has previously issued specialist guidelines on dealing with the birds, and has been struggling with the problem for years. The saving grace of the city is that seagulls do - occasionally - die. If seagulls stopped dying in the cold of winter or becoming sick, they would rapidly increase in population even further, and pose an even greater menace than they do currently.


If you've ever spent any length of time in large public transport stations in cities, you'll have seen pigeons. Lots of pigeons. Most of them quickly become a sickly gray-brown with pollution, and lots of them have missing eyes, toes or entire feet, and hobble around from day to day through various passenger stations.

sick pigeon

If all of a city's un-eaten pigeons rapidly became all shiny and healthy without a single defect, it wouldn't take much more than a year - perhaps two - for somebody somewhere, to notice. Although I personally would expect that they would notice the seagulls first.

And if I were to speculate about the identity of that remarkably observant person who notices it first... I'm fairly sure they will live in Aberdeen.

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    $\begingroup$ I think a lack of broken feet on pigeons might be noticed in London first, they are a particularly scruffy bunch down here. $\endgroup$
    – Separatrix
    Apr 28, 2017 at 10:10

It really depends, as Jarred mentioned in his comment if observation cancels and removes the effect it's not likely humans will realise anything is amiss.

However, I'm not sure making birds super healthy would really increase their lifespan at all (and cause any effect for people to notice).

Take this for example: https://www.rspb.org.uk/birds-and-wildlife/bird-and-wildlife-guides/ask-an-expert/previous/blackbirds_live.aspx

Apparently the average life expectancy of a blackbird is 3.4 years, yet they can live till at least twenty. Clearly birds aren't dropping dead of old age, and presumably at 3 years old they're pretty much in their prime so illness is less likely a cause of death than predation is.

How many birds do you see in your garden every day? And how many dead birds do you find? I can count on my fingers the number of dead (garden) birds I've found in my lifetime. Illness doesn't kill most birds, other animals do. Cats, birds of prey, humans are all far more dangerous to birds.

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    $\begingroup$ That, and general birdbrainedness -- CFIO (especially of the glassy variety) is way too common among avian populations, and birds sadly smack into man-made flying objects too $\endgroup$
    – Shalvenay
    Apr 26, 2017 at 23:38
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    $\begingroup$ Why wouldn't we notice the secondary effects? Seems like we'd notice missing worms, more nests, and whiter windshields. $\endgroup$ Apr 27, 2017 at 2:43
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    $\begingroup$ @BrianWoodbury would the obvious conclusion not be that there are more birds? $\endgroup$
    – OrangeDog
    Apr 27, 2017 at 10:27
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    $\begingroup$ @Shalvenay what's that CFIO you're talking about? My google-fu failed me on this one. $\endgroup$
    – Aaron
    Apr 27, 2017 at 12:32
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    $\begingroup$ My guess for "CFIO" was "controlled flight into objects", since it's similar to the common aviation term "CFIT" (controlled flight into terrain—a term which sounds much more dull than the event it describes). $\endgroup$ Apr 27, 2017 at 15:33

To add to BobtheAverage's answer (and others' answers), there are other groups that would notice, given time.

First, Wildlife Refuge and Park Ranger groups would begin to notice that birds aren't dying in the same ways they are used to seeing. These are wild birds in wild environments, but with both active and passive monitoring going on seasonally.

Healthier birds would tend to breed more successfully, so populations would increase, since disease and other natural causes would have less impact on their survival rates. Overpopulation would be noticed by a wide range of overlapping but different groups, from park rangers to bird watchers to hunters to farmers ("damn crows ate my crops again this season!"). And once the larger populations were noticed by these groups, various veterinarians would get involved; they'd study live and dead birds to determine a root cause.

Veterinarians. They'd notice. Within nanoseconds of any kind of public notice of population changes or possibly other "weird news!" events around birds, every. single. roadkill bird ever. gets sent to various regional veterinary diagnostic laboratories (VDLs). These VDLs saw a huge uptick in submission of random dead birds after "bird flu epidemic" news stories hit. And yes, many died of obvious causes like hitting a car or such. But each bird had to go through a necropsy, the animal equivalent to a human autopsy. Many of these laboratories (at least in the US) are run by public universities. The people who work in these labs are experts in their fields. They may not realize anything at first, but eventually someone with a bit more curiosity than the average person would start to notice "something odd."

I can assure you* that the pathologists in VDLs have a high degree of curiosity, that they tend to know "what's normal" for the birds native to their area, and that they have extensive -- often international -- circles of friends / colleagues that form an informal data-sharing network. They'd ask around and eventually start publishing detailed findings.

Once the first such story hit a peer-reviewed journal, everyone would know something was going on. They may not know WHAT yet, or WHY. But they'd know that things weren't right. And that would lead to further research and so on...

It would take time. And the press would get wind and distort the facts a great deal, leading to mass hysteria, etc. (see also, bird flu epidemic). But eventually they'd realize that something was going on.

*I worked in one of these VDLs for 15 years (in IT, but for the lab). In that role, I saw how people in that industry network and conference with each other for mutual support.


Humanity would notice something is off* within at most 1 year**.

While your tech avoids active observation, gathering statistics on birds, such as how many die/disappear is done by passive observation.***

enter image description here

*Less illness means less dead birds and more live ones. While some answers speculate that birds mainly die due to predation, that actually works in favor of noticing the effect, because predation affects the sick individuals far more than the others.

**Several kinds of birds come back to the same nest (or colony) for breeding season once a year, where they are captured every year to read the rings, weigh them, track which exact nest they go into, track how many young they have (which will get rings as well), etc.

*** In addition to the rings, there are countless bird monitoring programs where professional birdwatchers count breeding pairs for all species in an area, usually by walking through the area a few times during mating season and listening to the songs, and sometimes by spotting the birds.


Remember that in a stable population each breeding pair produces only one surviving pair of offspring.

That's in their entire breeding lives, no matter how many breeding cycles, no matter how many offspring per breeding cycle, two survive to produce their own two offspring in their turn.

If they produce more than that then the population rises, fewer and the population falls. Of course no population is that stable, there are booms and crashes. However population booms tend to cause population booms in predator numbers, so for humans to notice anything you'd have to look carefully into how often prey birds actually die of something other than predation or starvation. The answer is likely to be not a lot.

  • $\begingroup$ I think this would be the most quickly observed change that the general public would notice after one year. A bird who say lays 4 or 5 eggs and they all survive to become adults. That would appear to be an increase of 2 to 3 times just in new birds, which is still augmented by the parents generation who suffered very little losses as well. It could easily look like 3.5 to 4 times as many birds in one year. The next year would be 16x. Followed by 64x the next year. It would definitely be noticed... See "Torchwood Miracle Day" for reference. $\endgroup$
    – Rich Maes
    Apr 27, 2017 at 17:40
  • $\begingroup$ @RichMaes, what you'd see is a corresponding surge in predator numbers, then a drop in both until a new (unstable) equilibrium was reached. Slightly higher than before, but possibly not significantly higher. There's no indication in the question that the birds no longer need to eat and food/predation will remain limiting factors. $\endgroup$
    – Separatrix
    Apr 28, 2017 at 8:03

The answer is in the first sentence of your question. 2-3 years.

Ornithologists catch birds and mark (they literally put a ring on them) on a daily basis. They also put into a neat table the supposed age and description (general condition), then put number that correspond with description that is also on the ring.
So after two or 3 years they notice that previously sick birds are getting well. You don't need to catch the bird to watch it. They also notice that if they try to keep the bird for tests the sickness return. They also notice that when released the birds came back to full health.

This is called "Mantis effect" (no not, really I just made that up). You know the story that female mantis eats male head after copulation? They did that because they we're watched and it make them do silly things. So scientists will/would be able to figure out a way of examining the birds without holding them in captivity.

  • $\begingroup$ Commented by OP: "(...)if a captive bird is released and humans continue to monitor it, it won't regain its immunities or longevity unless and until humans lose interest." $\endgroup$
    – xDaizu
    Apr 27, 2017 at 13:10
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    $\begingroup$ @xDaizu Then I would be more worried about birds having an omnipotence or precognition abilities. $\endgroup$ Apr 27, 2017 at 13:21
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    $\begingroup$ Nonsense! Such things don't exist... They are just inhabited by omnipotent a precognitive alien nano-computers... (?) $\endgroup$
    – xDaizu
    Apr 27, 2017 at 13:24
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    $\begingroup$ Oh! If it's aliens then nothing to worry about. As they say "Keep Nano and carry on". $\endgroup$ Apr 27, 2017 at 13:36

The North American House Finch, and to a lesser extent the American Goldfinch, have experienced an outbreak of mycoplasmal conjuctivitis over the past 20-odd years:

House Finch eye disease was first noticed in 1994 by FeederWatchers in the Washington, D.C., area. Birds infected with this disease (also called Mycoplasmal conjunctivitis) have red, swollen, runny, or crusty eyes. In extreme cases the eyes become swollen shut and the bird becomes blind. You might observe an infected bird sitting quietly in your yard, clumsily scratching an eye against its foot or a perch. While some infected birds recover, many die from starvation, exposure, or predation.

Conjunctivitis can have many causes, but the type most often seen in House Finches is caused by the bacterium mycoplasma gallisepticum. This bacterium has long been known as a pathogen of domestic turkeys and chickens. The disease has affected several other wild bird species, including American Goldfinch, Evening Grosbeak, and Purple Finch.

enter image description here (Image from the above link)

The House Finch is a particularly common visitor at household bird feeders, and the symptoms of the disease are quite noticeable, particularly in advanced cases. (I've had outbreaks at my own bird feeder, so I speak from experience here.) The Cornell Lab of Ornithology runs Project FeederWatch, which is a crowd-sourced (flock-sourced?) data project that among other things tracks the prevalence of mycoplasmal conjuctivitis.

A sudden drop in the prevalence of mycoplasmal conjuctivitis would almost certainly be noticed by the data trackers at Project FeederWatch. Ornithologists would probably think up a few hypotheses for this collapse before they jumped straight to "alien invasion":

  • Perhaps the birds had adapted to be resistant to mycoplasma gallisepticum. However, the fact that this infection affects multiple species rules this out; why would both house finches and goldfinches simultaneously evolve a defense against the same disease? The rate of spread of the "disinfection" would also argue against this, as evolutionary change occurs over many generations of birds (i.e., decades if not centuries). If the technology came to earth simultaneously at multiple locations, that would look even more suspicious.

  • Perhaps mycoplasma gallisepticum had mutated to be a less virulent form, one that could infect birds without affecting their vision. (Bacteria can evolve much more quickly than macroorganisms, after all.) Scientists would then try to culture this new, less virulent strain in the hopes of isolating and describing it. They would already have a reservoir of mycoplasma gallisepticum in domesticated fowls, and finding a less virulent strain that was able to out-compete the known domestic strain would be a great boon to the poultry industry. They would quickly realize that mycoplasma gallisepticum had essentially died out in wild birds.

  • In an attempt to study this new-found immunity, they would perhaps capture wild House Finches and try to infect them with mycoplasma gallisepticum from domesticated fowl. These birds would manifest all the symptoms of the original disease, proving that this was not an evolved immunity. If the birds were still infected when released, and if they were banded for later tracking, they would be found to have been "disinfected" while in the wild. This would look exceedingly suspicious.

My guess is that scientists would know that something really weird was going on with wild bird disease within 5 years of the initial tech insertion, at least if it occurred in North America.


We would notice lifespans doubling. This would have at least the effect of doubling populations, and that would be quickly noticed.

Also, my cats would be happy and purring.

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    $\begingroup$ It would not double the number of birds because they are still competing for the same resources. Numbers would increase due to the lack of disease, but they would come no where close to doubling. $\endgroup$ Apr 27, 2017 at 1:25
  • $\begingroup$ @JarredAllen Probably true. I simply took the definition of "lifespan effectively doubled" at face value, as "the average number of years that a bird lives before it finally dies doubles." $\endgroup$
    – Cort Ammon
    Apr 27, 2017 at 1:29
  • $\begingroup$ How long would it take? less than 5 years? $\endgroup$
    – Monty Wild
    Apr 27, 2017 at 2:38
  • $\begingroup$ @JarredAllen it would still cause weird affects on the population, enough to be detected by population sampling. The birds would have an advantage against other species. $\endgroup$ Apr 27, 2017 at 2:56
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    $\begingroup$ Given the other answer's arguments about death from old age being rare, I don't think this answer is correct. $\endgroup$
    – kingledion
    Apr 27, 2017 at 14:09

The problem is that you'd need large scale statistics of bird deaths, but most bird deaths are so unimportant that they're not recorded.

To detect a trend, you'd need a large data source of unimportant, inane events. A microblog service with lots of users is ideal. People will casually mention a dead bird. Remember to normalise the data for any trends in number of users and what topics they talk about, and you can see if the number of bird deaths have gone down over time.

This has been done in real life looking at the number of people mentioning they have the flu on the microblogging service Twitter.

  • $\begingroup$ But as OP commented, the moment you start noticing them, they lose their immunity, so if someone start suspecting, it would be something like: "Hmmm... isn't it weird that none of these... oh, nevermind, one just died" $\endgroup$
    – xDaizu
    Apr 27, 2017 at 13:13
  • $\begingroup$ @xDaizu we're not searching for tweets of people remarking that birds are healthy, we're looking for (the decline of) tweets about dead birds they have just observed. $\endgroup$
    – Golden Cuy
    Apr 27, 2017 at 13:35

Even assuming that the nanites are so careful that they self destruct at any human-bird interaction, we would still notice. Indeed we monitor not only live birds, but traces left by them, for instance guano is harvested.

Even assuming constant bird population (because there is self-regulation, for instance when food gets scarce, birds have fewer offsprings), we could notice a decrease in bat bones in bat caverns.


Kinda ran through the discussion, so sorry if it hasn't been asked, but how long is the observation going? The easiest solution is to say that there is an uptick in endangered birds. Considering the United State's nation symbol, the Bald Eagle, is one of the most endangered and observed birds because of it's two statuses mentioned, it would be noticed overtime that the Eagles are not dying.

This also brings up another point that many birds are quite territorial (raptors especially, but even non-predatory birds like the Blue Jay, are aggressive attackers on anything entering their territory... and that is a wide swath of area), one has to wonder if the benefits these birds receive carry over to bird on bird physical attacks? The whole operation might be indanger of a never ending war over territory and food. Especially since predators of any kind will need a large supply of food, an increasing raptor population will encroach on human territory and there would be an uptick in pet deaths due to birds (the great Chihuahua genocide will ensue).

Also, while this does take into count captive birds, meaning farmed chicken and turkey are not going to be passed over, what about game birds? Will hunters the world over be taken seriously when their duck season starts to look feature ducks that can take bullets like Daffy Duck (I'm now picturing one of the first indicators is the homicide team standing over a duck hunter who apparently shot himself, believing he had "no more buwwets" because the ducks weren't getting killed by when he shot them)?

As for the cat question above, I would imagine that it would stop working as cats are notorious for playing with their food before the kill... the nanites would likely register this as captivity.

  • $\begingroup$ Welcome to WorldBuilding hszmv! The great Chihuahua genocide will ensue made me chuckle. Looking forward to your contributions. If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Jun 27, 2017 at 12:58

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