Use of sandbanks by terns in Queensland, Australia: a priority for conservation in a popular recreational waterway
Many terns (Laridae) from the northern hemisphere overwinter in Australia, but they are rarely covered comprehensively in bird counts in Australian coastal waterways. We conducted censuses over 3 years on terns in an increasingly popular recreational waterway at the northern end of Moreton Bay, known as Caloundra sandbanks, to provide the first overview of the relative abundance of non-breeding tern species on estuary-type sandbanks in Australia. The maximum number of birds counted was > 43,000, of which over 90% belonged to six species of terns. The most abundant tern species was the common tern Sterna hirundo longipennis which reached > 38,000 in one Austral summer. Other northern-breeding migrant terns were the white-winged black tern Chlidonias leucopterus ( > 17,000) and the little tern S. albifrons sinensis ( >11,000), which also breeds in Australia. These migrant terns arrived at Caloundra sandbanks at around late-October and a vast majority had departed by mid-April. Numbers were generally highest from late-December through to early-April. An additional three Australian-breeding terns of smaller population sizes frequented the sandbanks. Density of terns using the habitats could reach a peak of 600 ha−1 during the warmer months of the year, coinciding with peak human recreational activities. In light of the results, Caloundra sandbanks should be regarded as an Area of International Importance based on criteria contained in the Ramsar Convention. The situation at Caloundra sandbanks presents challenges to recreational and tourism issues, requiring review of traditional government priorities in the conservation of wetlands based primarily on waders.