How does a raven get intercepted?

Question

In “A Song of Ice and Fire”, there are many instances when some nobility sends a knight to deliver a sensitive message rather than send a raven, because a raven can get intercepted. I have no problem believing that it is possible to intercept a raven, but I imagine that this must a rather rare event - how is it that raven interception is such a real threat?

Based on the explanation given here, the majority of ravens are trained to return to a specific castle. If we assume that a raven would travel “as the crow flies” (i.e. in roughly a straight line), it is not clear to me how a raven would get close enough to another castle to be intercepted unless it deviates from its straight path. So I find it unlikely that they could be intercepted by flying to (or near) an incorrect castle.

Another possibility is that the “common folk” would shoot down a raven and bring the message to their lord for favor. For this to work, I imagine that either a message is large enough to be visible on a flying raven or that people try to shoot every raven they see in the hope of getting a messenger raven. I find the former unlikely due to weight ratios (they’re not swallows, after all), and if the latter were true I imagine that ravens would be rather rare due to overhunting, but I do not recall any mention of this.

Is there an in-universe explanation as to how raven post interception is likely enough to occur as to warrant sending knights instead?

Answer 1

By accident (usually)

People do sometimes prefer knights to ravens

“The first time I saw Riverrun, I was a squire green as summer grass,” Jaime told his cousin. “Old Sumner Crakehall sent me to deliver a message, one he swore could not be entrusted to a raven. Lord Hoster kept me for a fortnight whilst mulling his reply, and sat me beside his daughter Lysa at every meal.”

_{—A Feast for Crows}

However, they seem more worried about mishap than malice

It certainly seems possible to shoot down ravens:

“Unless Lord Frey tells him,” Catelyn said sharply. “Theon, when you return to my uncle, tell him he is to place his best bowmen around the Twins, day and night, with orders to bring down any raven they see leaving the battlements. I want no birds bringing word of my son’s movements to Lord Tywin.”

_{—A Game of Thrones}

And indeed, other people consider this a risk:

Catelyn knelt and took her father’s hand in hers. It was a big hand, but fleshless now, the bones moving loosely under the skin, all the strength gone from it. “You should have told me,” she said. “A rider, a raven…”

“Riders are taken, questioned,” he answered. “Ravens are brought down…”

_{—A Game of Thrones}

As to when someone would shoot down a raven in the hopes of getting a message, the answer is presumably if they are suspicious. If a raven flies over a battlefield, it might be shot down on suspicion of coming from the enemy. If a raven leaves a castle and there are spies in a nearby village, it might be shot down. If someone sees a raven flying during an hour when they are not usually active, that could also be cause for suspicion. The raven population will not be depleted, because only during certain times and places will it be worth the trouble to target any ravens one sees.

It’s important to note that this is not always (or perhaps usually) intentional, though. It seems likely more people shoot down ravens for food than for information:

Ravens did not always win through. Some bowman could have brought the bird down and roasted him for supper. The letter that would have set her heart at ease might even now be lying by the ashes of some campfire beside a pile of raven bones.

_{—A Storm of Swords}

When Stannis spoke of the risks to his ravens, he counted storms and hawks among the dangers his ravens would face.

Stannis turned to Davos. “The maester tells me that we have one hundred seventeen ravens on hand. I mean to use them all. One hundred seventeen ravens will carry one hundred seventeen copies of my letter to every corner of the realm, from the Arbor to the Wall. Perhaps a hundred will win through against storm and hawk and arrow.

_{—A Clash of Kings}

And, as we see from the previous passage, ravens are frequently brought down merely out of hunger.

It seems there are two reasons not to entrust a sensitive message to a raven:

• Sensitive messages are usually important. If 14% of ravens fall victim to misadventure, then the message is lost quite frequently. A knight may be killed, but perhaps not nearly so often.
• Accidental interception would be the main worry. If some hunter shoots down a raven for a meal, they are bound to notice the message. And if they can read (or know someone who can) and have loose lips, the message could travel to the ears of those who could use it for harm.

Answer 2

We know that in our world, carrier pigeons were used for hundreds of years as a way of communicating with a known distant place, even in wartime. The Wikipedia article I linked to gives an example of the Prussians using hawks to intercept carrier pigeons.

During the 19th-century (1870-71) Franco-Prussian War, besieged Parisians used carrier pigeons to transmit messages outside the city; in response, the besieging German Army employed hawks to hunt the pigeons.

Unfortunately, the citation given for that information is now behind a paywall, but in any case it is credible that hawks could be used to hunt carrier pigeons. It also seems reasonable that hawks could be trained to bring down ravens.

The Wikipedia article also mentions carrier pigeons being shot at during World War I

A carrier pigeon's job was dangerous. Nearby enemy soldiers often tried to shoot down pigeons, knowing that released birds were carrying important messages. Some of these pigeons became quite famous among the infantrymen they worked for. One pigeon, named "The Mocker," flew 52 missions before he was wounded. Another, named "Cher Ami," lost her foot and one eye, but her message got through, saving a large group of surrounded American infantrymen.

Military Falcons is an extract from the book Falcons by Helen MacDonald. It includes details of attempts to use of peregrine falcons during World War II to intercept carrier pigeons.

Presumably bows and arrows would have been used to try to shoot down pigeons in an earlier age, but with less chance of success. Soldiers who see what they think might be an enemy messenger bird are going to shoot at it with whatever they have, but a trained bird of prey is going to have more success.

If we assume that ravens take the shortest route to their destination, then a careful lord could draw all the routes between castles on a map and could place interceptors with hawks at places where enemy ravens would cross his territory but away from the routes of his ravens.

Of course, intercepting a raven in the dark would be almost impossible, so a clever lord would try to time the release of a raven to minimise the time it would spend over enemy territory during daylight.

Answer 3

They get shot down

I can't seem to find a clip of it right now but in Season 1 Episode 9, "Baelor", Theon Greyjoy shoots down a raven leaving the Twins. Afterwards him and Robb Stark have the following conversation.

Robb Stark: It's a birthday message to his grand-niece Walda.
Theon Greyjoy: Or so Walder Frey would have you think.
Catelyn Stark: Keep shooting them down. We can't risk Lord Walder sending word of your movements to the Lannisters.
_{Game of Thrones, Season 1 Episode 9, "Baelor"}

For more information on this GRRM has even said that ravens get shot down.

Because ravens are like the Internet of Westeros.
They’re an Internet that’s subject to hacking, with arrows and archers and shooting them down, and people killing the ravens, and messages not going through.
_{George R.R. Martin Answers Our Toughest Song of Ice and Fire Questions}