Dennis first became enamored of birds as a youngster in his native Costa Rica. Living in Central America, it is not difficult to see how ornithology could become the favorite science for any nature enthusiast, as there are well more than one thousand bird species in the region. He even has a passion for bird sounds and has a collection of them — he worked on the creation of a CD together with a talented pianist that mixes the piano with the sounds of the birds.

Dennis has lent his expertise to international institutions such as The National Audubon Society, The Organization for Tropical Studies, The Rainforest Aerial Tram, The Nature Conservancy Group, and The American Birding Association. His experience and knowledge has led him to guide in all countries in Central America and many others including the Caribbean, South America, New Zealand, Australia, Russia, Alaska, the Arctic, the Antarctic, Europe and Africa. He enjoys sharing his passion with passengers wherever he sails.