The Stephens Island Wren
This species of Wren was a flightless nocturnal bird that could only be found on Stephens Island near New Zealand. When the lighthouse keeper brought his cat, Tibbles, to the island, the feline set out hunting the birds and, over the course of a very short time, killed every one on the island and drove the birds into extinction.
Therefore, the Stephen Island Wren has the dubious distinction of being the only species on Earth wiped out by a single individual.
And now, on to the Hawaiian Crow!