Visitors to Thistle Island in 1877 found neither
little penguins nor
Australian sea lions, but did find numbers of
paper nautilus shells on the island's inner beach. Visitors to Whaler's Bay heard the calls of "hundreds" of little penguins from their anchorage there in 1904. In 1932, J. T. Mortlock gave an account from Whaler's Bay of the "mournful symphony of the curlews and penguins in the nearby cliffs". An account of a visit in 1928 wrote: "On Black Rock, at the north end of Thistle Island, we disturbed a large colony of seals, which rapidly scrambled into the water as the yacht passed by. Shags were plentiful. Many types of sea fowl were observed, including gannet, arctic skua, mollyhawk and stormy petrel." Former Lord Mayor of Adelaide
A. S. Hawker held a fishing record for a
tuna that he caught off Thistle Island in the late 1930s. Little penguin breeding sites were noted in a 1996 survey of South Australia's offshore islands, though the colony may have been recorded on Albatross Island, off the island's southern tip. The island is the home to an introduced population of the
greater bilby, originally bred at
Monarto Zoo. By October 2020, the population was thriving so well on Thistle Island that it was possible to trap nine bilbies for relocation to the
Arid Recovery Reserve near
Roxby Downs, to help boost the
gene pool there. == References ==