The Conversation
Drethnor seems totally intent on the bird men this turn, which is good, their numbers are small enough that inbreeding really would be a problem in coming turns. However he either is unaware of the changes taking place in the human tribe, or feels they need time to settle down more before he acts. As the game master sometimes it's hard to tell exactly what the player has noticed and what has slipped by him completely.
The deal with using the soul was fairly clever. It really cements the relationship between the dread vultures and the bird men, even if the human tribe drops keeping these pets altogether the Vulture Men are likely to keep them forever. More importantly vultures guided by human minds are likely to be looking at things more interesting to Drethnor. After all the player isn't so very interested in dead elephants these days!
But the second action was more telling. The player made a very bold and daring move to address the low population. His solution was actually ideal but it came with some costs. The act was very complex and finicky. In order to get the numbers he really needed Drethnor had to make a deal with the game master. Deals like this can be dangerous but Drethnor is used to rolling with the punches and he managed to get a promise that whatever happened the change would not destroy his bird man population. Next turn he'll see what this devil's bargain actually got him; but he can already be sure that I'll take the opportunity to put my own stamp on his new race!
Most of the time the game master has to act within strict boundaries. It's his job to interpret what the players are doing and how the people would logically react. We have a lot of power within those limits, but the limit is very real. Given the real earth context I can't make up a race of giant carnivorous bats, they have to be made by some player or already exist on ancient earth before I can play with them. Now however I, as game master, get to take an active part in shaping what could be a major intelligent race upon the globe! It's very exciting.