Depending on where you are it can be illegal as it is considered to be interfering with nature.
Birds of prey will attack a UAV even as big as the TH.
Your photos are awesome looking. My question to you is how were the pelicans reacting to the presence of your TH? Were they frightened, indifferent, or interested?
We get huge flocks of them where I go in Florida. At the beach near St. Augustine it is fun to watch them fly in formation along the breaking waves hunting for fish.
Is there a technique you use to approach and fly with them?