Birnie and Sydney Islands are reported to have been discovered in 1823 by a “Captain Emmett”. This may have been the Captain Emmett (or "Emmert" or "Emment") of the British whaler (or the "Sydney"), who may have named the islands after the ship and its owner, the London firm Alexander Birnie & Co. Alternatively, it may have been Captain William Emmett, from Sydney, who sailed regularly in the area and is known to have bought the brig "Queen Charlotte" from the whaler James Birnie (of the Birnie ship owning family) in 1820. Frenchman Louis Tromelin came upon Sidney's Island, either in 1823 or 1828, and placed it at 4°26'30", 171°18'; he went on to survey Phoenix Island.