The lizardly green monster is a frightening omnivore, eating just about anything he comes across. When he discovers a helpless human infant, however, he stops his relentless consuming to take a closer look. Something about the wide-eyed baby reminds the creature of himself. Instead of popping the child in his mouth as a snack, he adopts it instead, placing the newborn high up in a bird’s nest and teaching it the first rudimentary lessons of survival. Then he clumsily falls to his own death, leaving it up the baby to put into practice those few lessons he’s learned. Eron Sheean’s created a vibrant computer animated world of fiction here, populated by all sorts of highly-detailed creatures, both real and imagined. Not exactly a charming kid’s show, “Fledgling” is nonetheless a captivating study of nature’s neverending cycle of life and death. Marlon Perkins is almost certainly here in spirit.