Tags: Thalasseus bergii. Crested Tern. Birds. Wildlife. Native. Australian. Queensland. Moreton Bay.
Crested Terns are a common sight on Bribie Island and are often seen flying over saltwater areas or roosting on sandy beaches and manmade structures. A good place to observe them in flight is from the Bribie Island Bridge which is a frequent hunting ground. They can also be observed following behind prawn trawlers coming into port. During late Spring and early Summer, many birds leave the island to breed elsewhere.
In Australia Crested Terns sometimes referred to as Greater Crested Terns are second only to Caspian terns in size with a length of 43-48 cm and weighing 275-371g. Blackcaps with tousled crests and yellow bills are prominent features for identification. Caps are less black during the nonbreeding season. Wings are long and pointed and tails are forked. Adults are similar in appearance which changes slightly during the breeding season.
Similar to Crested Terns are Lesser Crested Terns which are smaller with shorter legs and a more orange bill. Crested Terns are found in most coastal areas in Australia, on offshore islands and frequently on inland rivers and lakes as they feed in fresh as well as saltwater. They also inhabit the islands and mainland areas in the Indian Ocean and the coasts of South Africa.
Fish are their main food source, but they will also eat baby turtles, eggs, squid and crabs. They fly 5-15 metres above the water and when with their keen eyesight spot a fish, they dive headlong into the water taking their prey at depths up to a metre. Fish 5-8 cm are grabbed at the back of the head and swallowed in mid-air. Breeding takes place mostly on offshore islands in large colonies with other Tern species and Gulls.
Nests are just a scrape on the sand with no lining and made very close together. During the courting period, the pair appear to dance together, and the male offers the female fish as part of the ritual. Clutches of up to 2 mottled brownish eggs are laid and incubated by both parents for 25-26 days. Both parents care for the young and after a few days, the chicks can leave the nests.
They fledge at about 38-40 days but remain in the care of their parents for about 4 months. Nest sites often change each year with some birds moving up to 200 km to a different site. Many of the eggs are lost to hungry gulls and ibises. The scientific name Thalasseus is derived from the Greek Thalassa which means sea and bergii are named after the scientist Bergius who studied the terns in South Africa.
Crested Terns are widespread and common around Australia with the population remaining stable. The conservation status is secure.