After hearing these things making a huge racket in the trees around and about I finally managed to get a picture of the Cicada.
The shell in the background is the shell they live in before breaking out of the back of it, shedding the skin and becoming the beautiful creature you can see in the foreground. This is just an annual example but others are famous for having a life cycle of either 11 years or 17 years apparently with a vast number appearing periodically. They make a particularly unique sound with a long lasting rattle that rises in pitch.
For the last week we have been in a different classroom for the BST and we got this picture of a nest literally right outside over the boardwalk: