On April 7, volunteers surveyed both confirmed and unconfirmed sites in Casuarina, Kwinana, Wandi, Wellard, Cooloongup, Karnup, Port Kennedy, Rockingham, Secret Harbour, Waikiki, Warnbro and Baldivis.
In the southern suburbs (covering Rockingham and Kwinana), only 932 cockatoos were found, the lowest number to date.
In 2013, 58 sites were surveyed in the southern suburbs (19 in Rockingham and Kwinana) and active cockatoo roosts were recorded at eight locations.
The southern suburbs population went into freefall from a high of almost 1900 birds in 2010 after two major nests in pine plantations in Baldivis and Karnup were cleared.
In 2011 and 2012, the count dropped to around 1150 cockatoos.
BirdLife Australia’s threatened cockatoos project manager Matt Fossey said Perth’s rapid expansion was detrimental to cockatoo populations.