There are three species of loons that have been spotted in Connecticut: the Common loon, the Red-throated loon, and the Pacific loon. The common loon is the most likely to be seen, as it is the most widespread species. The red-throated loon is slightly less likely to be seen, as it prefers more northern climates. The Pacific loon is the least likely to be seen in Connecticut, as it is more commonly found near the coast of Alaska.