In the spring, wrote Alfred Lord Tennyson, “a young man’s fancy lightly turns to thoughts of love,” and this may oftentimes be true. But here, on a sometimes-blustery island in the Salish Sea, thoughts of love have long since been acted upon by the time spring comes around. On San Juan Island, spring is the season of wild puppies. The foxes here come in two main styles — red and black — although all are members of the species Vulpes vulpes, which is commonly if confusingly known as the red fox, regardless of what color an individual actually is. When a San Juan Island fox has one red parent and one black parent, the result is a charming mixture of the two morphs, although they always have a white tip on their bushy tails. The foxes were introduced sometime in the mid-twentieth century, probably to control the rabbit population, who were in turn introduced some years before that, probably to provide sustenance for the lighthouse keeper. As it turns out, the lighthouse keeper’s appetite …