Despite its name, this group of islands lying offshore between Bundaberg and Rockhampton is closer to the southern half of Queensland than it is to the city of Mackay. The Mackay–Capricorn Islands comprise the section of the Great Barrier Reef known as Capricorn Marine Park, which stretches for 140 km (87 miles) and cuts through the Tropic of Capricorn, Heron Island being the closest point. This is a great area for wildlife: turtles use several of the islands as breeding grounds; seabirds nest here; and humpback whales pass through on their migration to Antarctica each spring—generally between July and October.