The population size of the southerly subspecies had been reduced to about 62 individual birds in 1990 and the first study of the population structure undertaken from 1988 to 1992 indicated their significant decline. Conservation measures were put in place involving the poisoning of feral cats and the population has gradually risen, with about 250 individuals being recorded in 2005. The northerly subspecies has a wider range and its population was about 1300 in 1989. It had recovered to about 1700 individuals by 2004 but only as a result of intensive management.