The site has been identified by BirdLife International as an Important Bird Area (IBA) because it supports over 1% of the world populations of little penguins (with up to 26,000 birds), short-tailed shearwaters (up to 450,000 pairs) and Pacific gulls (with an estimated 52-490 birds). In the past it was occasionally visited by small numbers of orange-bellied parrots.[2] One of the largest breeding colonies of crested terns in Victoria (2800 pairs) is at the Nobbies. Pied and sooty oystercatchers, as well as hooded plovers, use the beaches.[1]
The colony's population has fluctuated over time with changes in land use and tourism practises evolving. A 1918 count estimated 200,000 birds. By 1987 the population had plummeted to 20,000.[3] In 1940, the population was believed to have dropped from approximately 2000 birds to 200 rapidly due to a disease or pathogen,[4] though these figures are inconsistent with the scientific literature.
In 2011 the colony was estimated to contain up to 26,000 birds.[2]
An early detailed account of a visit to the colony was written by Donald Macdonald and published in The Argus in 1902.[5]
The high public profile of the colony has assisted conservation efforts; as has its economic value as a tourist attraction. In 1987, more international visitors witness the penguins coming ashore at Phillip Island than visited Uluru. In the financial year 1985-86, 350,000 people saw the event, and at that time audience numbers were growing 12% annually.[3]
