The Boulders Penguin Colony was established in 1983 and numbers increased from surrounding island colonies to bring breeding numbers to 3 900 birds in 2005. Since then there has been a decrease. The 2011 figures sit at around 2100 birds at Boulders Penguin Colony. The decline at Boulders and the global decline is the suspected result of:
* habitat destruction
* effects of oil spills and other marine pollution
* impacts of global warming on fish stocks and fish movement
* overfishing
* irresponsible tourism activities
* domestic pets/animals
