Green Tree Frogs

My new additions to the family have settled in well. They seem to like their new surroundings. However Mack and Sooty are beside themselves.
What are these new invaders and they look like they would be very tasty morsels. How come I can't get at them?
You should see the cats when the frogs decide to croak.
I hope I'll be able to take advantage of the photo opportunities I can see coming up. I'm usually too slow though.