Peter, to deal with the last issue, more messing with you. We are the primates and I was just being sarcastic.
The birds and other species more sensitive are definately in our concerns. You might have missed that there was a big time dis of Beautiful Belize, if I have it right. A book of photos of over views of animal(mostly on the mainland) taken by the same ultralites on the Island. It became a big "dislike" on facebook from a lot of people that discovered that these photos were made by the ultralites and disturbed the animals.
Safety wise, it is a no brainer. Even though we don't subscribe to it now, you can probably on-line, AOPA, the magazine of Private Pilots, has every flight disaster, every month, and you can find out the truth. It is definative...never fly in an ultralite and never go up in a balloon. The stats are there.