Kurroka

Kurroka is a species of birds used in Alma to send messages. They were domesticated at least in the Old Era, although it is possible that their use is even more ancient. Who first came up with the idea and how they learned to train them is, therefore, unknown.
The females are characterised by dark-blueish plummage, and only they are used for communication. The males have a very garish plummage and make loud noises, both of which characteristics were deemed undesirable for a bird that is often supposed to go unnoticed, carrying secret messages.
Whilst Kurrokas could fly long distances and were very strong. They could survive in most of the climate zones accross the continent except for the far north. The challenge that came up was that they could become easily distracted on the way to the next location, especially with food, or an opportunity for a new mate. As a result, in the end a network of stations was established that covered most of the continent west of Yuulón Mountains.
In the station, Kurrokas had a mate they were bonded with, and food delicacies - conditions which assured they would go where planned. Female Kurrokas therefore had a bunch of males, a different one at each station on their reular routes, whilst males had a number of females visiting them. The males held at the stations would be only flying in the close vicinity and come back regularly to be fed. All the countries recognised the benefits of having a well-established and reliable communication network, so they respected the messages once they arrived at a station and an international crew was often taking care of them. Of course breaches of confidence occassionally did happen, but they were very severly punished.