Gulls and Terns (Laridae) off Wollongong. New South Wales: seasonal abundance, scavenging behaviour and depth zonation

During 23 monthly pelagic cruises off Wollongong, Silver Gulls Larus novaehollandiae comprised about 90 per cent of 11 483 larids counted and were the most dominant scavengers. Gulls were mainly inshore whereas terns were mostly offshore and pelagic. Five tern species were seen irregularly. Crested Terns were consistently more pelagic than neritic while not breeding and consistently more neritic than pelagic while breeding. Numbers of Silver Gulls increased markedly in winter (before breeding) when zonal distribution changed to partly neritic, partly pelagic. At peak abundance in June 1985, their rates of encounter in pelagic and neritic zones were equal. It is suggested that the Silver Gulls in the pelagic zone were mainly adults, scavenging for nutritious food before breeding.

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