How the blue, flying animals take the homes of the animals that fly and hit at wood with their head

Flying animals that hit their head at wood are important to areas with lots of trees because they make homes in trees for themselves and other animals. The Black Backs are a type of these head-hitting flying animals. There are not a lot of Black Backs in the world. Blue, flying animals like to take over the homes of the Black Backs. We watched lots of moving pictures to see how they did that. With this, we can help the Black Backs keep their homes in places with lots of Blues.