Discussion of level 4 monsters.

It's good to use birds to quickly traverse the map, but it's better to acquire them at a field dwelling or in a built neutral/enemy town – they are more expensive to build, and lightning doesn't always help. And one hippogryph today, even posthumously, can turn out to be more useful than two birds tomorrow. Also, the speed of hippogryphs in an army is the same as that of hippogryphs, and birds without support won't last long. They block archers well, but if you send them into the thick of the enemy, they aren't griffons, and they might retreat ingloriously.