Let's assume that there's a species of eagles that's about the size of an Andean Condor (about 3m wingspan, 1.5m length, 10kg) and that there's a culture that has managed to tame this creature (or domesticate it, depending on what's realistic). Technology is preindustrial with early steel metallurgy, i.e. early middle ages; and the world is completely earthlike.

Considering that dogs have been used extensively for war efforts in all kinds of situations, from support and guard duty to combat, from assault to clean-up. And that eagles have been used to hunt animals as large as wolves and there are reports of eagles hunting children. How plausible would it be for the aforementioned culture to use these eagles in battle? how would they most likely be used?

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    $\begingroup$ xkcd.com/1842 birds of prey have already been used to take down drones. $\endgroup$
    – apaul
    Commented May 30, 2017 at 17:37
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    $\begingroup$ Weaponizing peregrine falcons to dive bomb enemy faces is probably better than large eagles. They're much smaller, easier to maintain and faster, ergo harder to hit and more likely to survive combat. $\endgroup$ Commented May 30, 2017 at 20:24
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    $\begingroup$ unless you can teach them how to dodge arrows or air projectiles, a eagle with thoes dimentions arent much usefull in battle, i can imagine them being a little usefull if you can train them for hunting, for exemple they can hunt for animals for your troops to eat, or even carry heavy bagage that would normaly take days if it was talken on foot or by horse. Other then that i dont really see them being usefull $\endgroup$
    – jeyejow
    Commented May 31, 2017 at 9:11
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    $\begingroup$ A word from an archer. The arrowhead commonly used to hunt birds is the blunt. The point is that a flying bird's body is built to reduce weight, with very light and fragile bones. Penetrating arrowheads would make the arrow pass clean through. The impact of a blunt head, on the other hand, will shatter a variety of bones, with all the energy of the arrow transferred to the target. (Additional side effect is that your arrow drops nearby, ready to be reused.) Even a hit somewhere on the wing will bring the bird down. And a 3m wingspan bird is a very large, easy-to-hit target. Just sayin'. $\endgroup$
    – DevSolar
    Commented May 31, 2017 at 9:12
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    $\begingroup$ Just make sure that when the eagles attack, someone shouts, "The Eagles are coming!" $\endgroup$
    – user96551
    Commented May 31, 2017 at 10:27

7 Answers 7


There are a number of ways they could be used, but maybe not in ways you would expect.

The biggest problem with military birds is that they can't be armored enough to protect them from archers. Any armor that could deflect an arrow is going to be too heavy, or just plain in the way. Birds of that size are going to make a substantial target, very inviting to a bored archer.

So if you have to spend your time avoiding archers, what do you do?

Carry Messages: Information is the lifeblood of any campaign. A bird will be able to get back and forth to the front relatively easily and without the risk associated with a ground based messenger. Conversely, they can be trained to hunt enemy messenger birds. At the size you are talking, they aren't going to be prey for your enemies airforce, while your enemies messenger birds will be a light snack for the eagles.

Harass enemy infantry: Hit them while they are encamped for the night. Hit the sentries to make them paranoid and maybe not paying to close attention. Hit troops at random while they are trying to set up for the night. Train the birds to go for the eyes. This is an injury that can take a man right out of the fight to come and can be done in a fast pass.

Hit the Baggage Trains: Baggage trains mean pack animals. There are a lot of pack animals that would panic at the sight of a 3 meter bird, especially if the bird is going for their eyes. If you can hit disrupt the baggage train, the whole enemy campaign will fall apart.

Those are the biggest uses I can think of. Just use them in places where the archers aren't going to be.

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    $\begingroup$ All good options, but I think there would be other creatures better suited for most (though the baggage train is a good idea, I like that), pigeons are much better suited for carrying messages due to their speed and some kind of owl would likely be better for attacking at night. $\endgroup$ Commented May 30, 2017 at 18:58
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    $\begingroup$ True on both points. The OP was talking specificaly about eagles, so I stuck with that. Now if He went all bird crazy, well...I'd try to figure out how to work ravens in there somewhere, falcons for message intercept, owls for night strikes, and so on $\endgroup$
    – Paul TIKI
    Commented May 30, 2017 at 19:35
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    $\begingroup$ Pigeons can't eat enemy pigeons in mid-flight. Carrier kestrels sound like great fun, though. But, when your enemy has carrier kestrels, you need a bigger caliber even. $\endgroup$ Commented May 30, 2017 at 21:46
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    $\begingroup$ The arms race (wings race? :P) might be a fun aspect to play up. $\endgroup$
    – Michael
    Commented May 31, 2017 at 17:37
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    $\begingroup$ @PaulTIKI I assume most of the time, when you shoot a bird, that bird is on the ground or in a tree. It's completely different than when they're flying in the air. $\endgroup$ Commented May 31, 2017 at 19:22

Presuming the bird can fly higher than an archer can shoot an arrow; you can use them for artillery if nothing else: Eagles have sharp eyesight and superb positional awareness in the air (they know when they are precisely over a fish in the water far below, in order to dive for it); and most birds can readily carry about 50% of their weight in flight; birds of prey often their full weight.

For a A big bird like this, train it to fly high over enemy troops and drop a load (like 50 pounds worth) of arrow-like missiles, finned for proper flight orientation with a heavy, sharp head. About one pound. You can even design the finning to create some dispersal over the target. from 1000 feet (about 100 stories, so not as high as it sounds) these will strike with devastating force.

Specifically, the impact energy of a 1 lb weight (.45 kg) dropped 1000 feet (about 305 meters) will be 1345 Joules; compare that to a 45 caliber bullet with an impact energy of 458 Joules. The drop will take about 7.9 seconds.

Of course, with that kind of energy, the projectiles could be just rocks, but if they are sharp they will likely penetrate shields, armor, helmets and horses.

This type of training is simple enough to be feasible for birds; especially a raptor (generally smarter).

The eagle will be safe and can return for its reward and a short break before it flies again. A squadron of these? A handful of birders could defend against an army.

Added: A bald eagle can cruise at 10,000 feet, ten times higher than the 1000 feet I mentioned.

Also: Weight birds can carry. A 20lb Harpy Eagle routinely carries 20lb, and has been observed carrying 40lb. A Great Horned Owl routinely carries 3 times its own weight. The OP had a scaled up bigger bird; if it is strong (like a Horned Owl) and 10kg (22 lb) it could plausibly carry 50lb. And if 1000 feet wasn't high enough, or we wanted to cut the weight in half; we could double the height to 2000 feet, and get the same impact. (impact is g x mass x height (in kg and meters), g is a constant, so half the mass, twice the height for the same impact...)

Additional: In response to comments about terminal velocity limiting the impact, I add this: This Wiki entry on terminal velocity says a speed skydiver can reach speeds of 530 km/h, a sharp, heavy dart-like object should be able to match that speed. It requires 1105 meters for 530 km/h to be the terminal speed of a gravity drop. That is 3625 feet; for any weight. Below that height (my examples were 1000 ft, 2000 ft) height does help. I am not talking about a typical archery arrow (which is not heavy); we want a point-heavy sharp object with orienting fins (but the faster the terminal speed, the smaller the fins can be); six inches would probably suffice. More of a heavy dart, in fact perhaps an iron or steel conical shape would be properly oriented within the 7-12 seconds the drop would take.

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    $\begingroup$ I'm somewhat doubtful of how much weight an eagle could carry. According to this site the most they are likely to lift is four or five pounds but they are only able to pick up the heaviest weights during a fast dive and I doubt they could carry something very high or for very long. $\endgroup$ Commented May 30, 2017 at 19:12
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    $\begingroup$ @adaliabooks Consider answers.com/Q/How_much_weight_can_the_strongest_bird_carry The OP is talking about a fictional bird; and a Harpy Eagle (20lb) routinely carry 20lb, and have been known to carry 40lb over short distances. Great Horned Owls routinely carry 3 times their weight. I figure the OP's fictional bird is strong; at 10kg it weighs 22lb, and 2.5x its weight is not unreasonable. Of course, different weights or number of projectiles does not change the utility of the idea; even at 1/3 the weight they hit with the killing power of a 45 bullet. $\endgroup$
    – Amadeus
    Commented May 30, 2017 at 20:03
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    $\begingroup$ It may be worth noting that a culture that has domesticated attack birds has probably bred birds specifically for the purpose (just like cultures that use war dogs). So the army has selected for strength and aptitude. Also while large projectiles like you suggest would cause major damage to whatever they hit (and thus might be good for fortifications), a wider spray of smaller "shot" could cause serious damage and destroy morale for a fixed formation like archers or spearmen, and could wreak havoc on mounted cavalry if the horses had not been trained against such attacks. $\endgroup$
    – bstpierre
    Commented May 31, 2017 at 3:16
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    $\begingroup$ And don't forget the counter, intercepror eagles that attack the bomber eagles. And counter-counter, escort eagles. $\endgroup$
    – Odalrick
    Commented May 31, 2017 at 8:54
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    $\begingroup$ They could drop pottery bowls with something flammable, such as oil, grease or tar, from high above. These pots wouldn't be too heavy, and you could set fire to a city, or much more easily, to the enemy camp. Or drop incendiary projectiles in the middle of stables, and where horses are gathered for the night, causing havoc. $\endgroup$
    – Rekesoft
    Commented May 31, 2017 at 11:15

I'm going to say that eagles, even giant ones, aren't going to be much use in battle.

Training an eagle for battle is presumably going to be a fairly time consuming and expensive process. Most eagles don't reach maturity for about 4 or 5 years so you've got to invest a lot of time to get a battle ready bird. Depending on what kind of training they would need and when they could start that training they might need even longer than that.

But the first time you use them in battle they are likely to be killed as all it would take is one arrow (and they are large targets and don't fly all that quickly) or a hit from a blade. If you're lucky they might maim or kill someone first, but that's a hell of a lot of effort for what amounts to a single use weapon.

They might be useful for some other purpose but I can't quite think of anything at the moment that they would really work for.

  • $\begingroup$ The same could be said about dogs, what made dogs a viable option that eagles don't have? if anything, dogs are an easier target to hit. $\endgroup$ Commented May 30, 2017 at 17:51
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    $\begingroup$ @Miguel Bartelsman : dogs are stronger, more resistant, easier to breed and can easily tackle any enemy. $\endgroup$
    – Keelhaul
    Commented May 30, 2017 at 18:00
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    $\begingroup$ There's also a psychological aspect to being charged by an angry dog; most people have experience with a dog showing aggression. While getting mauled by an eagle is certainly no picknick either, just seeing it up in the sky isn't likely to inspire primal fear in the average soldier. Is that eagle coming for you? Maybe, not easy to see. Is that dog coming for you? I don't know but I'm certainly not hanging around to find out! $\endgroup$ Commented May 30, 2017 at 19:05
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    $\begingroup$ How many of those people charged by a large dog are carrying a weapon, or wearing armour and near several friends similarly equipped? Soldiers know that they are capable of taking down all but the largest dogs relatively easily. $\endgroup$
    – Sarriesfan
    Commented May 30, 2017 at 19:53
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    $\begingroup$ Dogs aren't incredibly useful in combat when there are guns. It's their noses that provide value. $\endgroup$ Commented May 30, 2017 at 20:09

I'll try to point out some behavior known birds of prey exhibit that side X could use to thwart Y without any domestication/training.

PBS's Nature had an episode about Harpy Eagles and the film crew had to wear a good amount of protective gear to avoid getting jacked while climbing up towards their nests and being relatively vulnerable to attack. In a wide-open space, they're probably easy to thwart with a bow or bullet, but the crew noted that simply finding the eagles in the dense jungle was difficult. Set your battle in the jungle, they'll blend right in.

There's also a curious thing about how hawks are good for hummingbirds via the cliche "the enemy of my enemy is my friend". Hawks eat jays that eat hummingbirds, but the hummingbirds are too trivial of a snack to bother the hawk. Researchers found that hummingbirds that nest near hawks have a 46% chance of fledging young vs. 9% of those that don't, a dramatic increase. This is a bit harder to use on tribe X vs Y given they're both species Z so can't be as dissimilar as a jay (120 g) and hummingbird (3 g).


Manco inca Yupanqui (1516-1544) was made puppet Inca by Francisco Pizarro in 1533. Manco led the great Inca revolt and beseiged Cuzco in 1536.

The Incas ambushed and defeated four relief expeditions sent by Pizarro, killing almost 500 Spanish and capturing others, along with weapons, guns, armor and horses.

Defeated, Manco retreated to Vicabamba and founded the Neo-Inca State that lasted until 1572.

There were probably many places on the mountain trails leading to Cuzco that were good spots for ambushes, with mountains on one side and chasms on the other side.

I remember reading a review of a fantasy novel some time ago. It quoted a scene from the novel. An expedition of the 19th century Royal Navy was somewhat out of it's element in the high Andes mountains. The protagonist was a little girl who was important for some reason, and was escorted by a boy midshipman her age. The expedition was being attacked by flying creatures of some type and people were being carried away or knocked off the path to fall thousands of feet.

And I remember the Battle of the Five Armies in The Hobbit. When the eagles arrived they knocked goblin warriors off the mountain to their deaths.

So if the enemy is crossing the mountains and is on a narrow path with a chasm to one side, an attack by giant trained war eagles could spread panic and confusion. The goal would be to get people and especially animals to panic and stampede and knock each other off the path into the chasm. Perhaps they could slow down the mountain crossing of the enemy army until the campaigning season was about to end and they had to turn around and go back without accomplishing anything.

In a medieval society warriors often wear armor of some type, and mounted warriors often ride horses or other creatures that wear armor. but transportation animals, that pull wagons or carrying loads on their backs, don't wear armor because they don't go into battle. Thus it would be easy for giant war eagles to bite and claw the transportation animals and stampede them.

At the Battle of Glorietta Pass, New Mexico, on March 28, 1862, Rebel forces drove the Union forces back and captured the pass. But a Union detachment reached the Rebel rear and the rebel wagon train. They burned 80 wagons and their supplies, spiked the cannon, and killed or drove off 500 horses and mules.

Without their supply train the rebels eventually called off their invasion of New Mexico and retreated down the Rio Grande to Texas.

Destroying the enemy supply system can force them to abandon their campaign.


They could be used to drop rocks, as already mentioned. If your army wore a uniform, then you could train the eagles to attack people not wearing that uniform. They could fly higher than the archers could shoot, which would provide even more force in the rocks. Even if they don't penetrate, the rocks could do major damage. The eagles could be trained by putting food on enemy prisoners, and then giving them more food afterwards. All in all, it would be a very effective early air force. It could have been deployed against the mongols, and potentially stopped them in their tracks. It would take time to train them, but it would be effective after that time. Also they could be trained in a group, which would save time and money. It would be difficult, but when mastered effective. Besides, it would be cheaper and more accurate than catapults.


I'm a little late to the party here, but eagles wouldn't be good to use in war for a variety of reasons. As already mentioned, people wear/wore armor, not much an eagle, even a large one could do against metal armor. As for dive bombing and knocking people about, you'd be better off doing exactly what they did in the past, using slings or just throwing rocks.

You also have a training problem. The way you train raptors is food based. You have to get them to want to attack people thinking they'll get rewarded. That will be hard enough to do as humans aren't their prey. But even if you got them trained for that, you take them out to the battle field and turn them loose, watch them soar off... And immediately turn around and attack the nearest human, maybe your buddy on the front line. You're probably gonna say "well train them to recognize certain uniforms or at least the enemies as their target". Uniforms weren't always a thing.

Eagles would still probably be too afraid to actually attack on a battlefield. Even if you got them to attack "guards at night" or whatever; while eagles have extremely powerful grip, but it doesn't take much to kill one in return. They could do some major damage, but they also might not do much at all.

IMHO as a falconer, the resources and time it would take to train an eagle to be used in war against people isn't worth it. It is probably why they weren't used. They have to eat meat and even smaller raptors can eat enough meat that could have been used for a soldier. A large eagle would likely eat enough meat daily that a soldier would eat. I'd rather have a soldier than all the issues I mentioned with the eagle.

So, what about supply/pack animals as others have mentioned? Take a guess. Not work it. You're gonna have people guarding the supply. Give a few of them a rake of sorts and swat them when they swoop down. Not much even a large eagle is going to do to a horse even if it hits one. Kill the eagle and you just wasted your enemies resources more than they could have wasted yours. In fact, let the eagle live and they'll continually have to waste their fresh meat on it.

So anyways, hate to be a party pooper but eagles aren't really worth the effort.

On the other hand, having trained falcons could be useful against enemy pigeons and in fact, peregrines were used to kill Nazi pigeons in WWII.


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