Messenger wyvern

Messenger wyverns were part of Safehold's communications system since the Creation. The original messenger wyverns had been genetically engineered by Pei Shan-wei's terraforming teams to deliberately enhance the various breeds' natural capabilities for the specific purpose of creating a low-tech means to help tie the original, scattered enclaves together.

Bigger, stronger, and much tougher than Old Earth's carrier pigeons, the wyverns Dr. Pei designed fell into two main categories, either of which could carry considerably heavier messages than their Terran counterparts. They could even be used to carry small packages, although this was not considered the most reliable possible way to deliver them.

Short-range
The short-range breeds were faster, smaller, and more maneuverable than their larger brethren. Capable of speeds of up to sixty miles per hour, their maximum effective flight range was mostly under six hundred miles, which meant they could deliver a message to their maximum range in as little as ten or eleven hours, on average. Some of the racing breeds had been clocked at over a hundred miles per hour in a sprint. They were the most commonly used breeds, in large part because the logistics meant there was little call for ranges longer than that. Like carrier pigeons, they were a one-way communications system, since they returned only to the wyvernry they recognized as home, wherever that might be, which meant they had to be transported from their home to their point of release. Shuttling them back and forth by wagon or on lizardback over distances much greater than six hundred miles simply wasn’t practical for most people, although the Church of God Awaiting and some of the larger mainland realms maintained special relay systems to supplement and back up the semaphore towers. In addition they could be relatively quickly imprinted with another home wyvernry.

Long-range
The longer-range wyverns were slower, but they also were capable of flights of up to four thousand miles. Indeed, there were rumors of legendary flights of up to five thousand, although substantiation for such claims was notoriously thin on the ground. Because they were slower and because they had to stop to hunt and roost on the way, they were capable of no more than seven hundred and fifty miles per day under average conditions, but even that meant they could deliver a message over a four thousand-mile transit in less than six days. That was slower than the semaphore, when under good visibility conditions, but faster than any other means of communications available.