Plants And Animals - Seabirds

Abstract
Threats to Seabirds
Actions Needed
Regional Comparison
Species Summaries
More Information
Authors
Contact

Documents for download from this site are in PDF format and you will need Adobe Acrobat Reader to view them. The reader is free and can be downloaded from the Adobe website.

Little Penguin Eudyptula minor
(Photo: Tony Robinson)

Abstract

Seabirds are significant, but often forgotten and little appreciated elements of South Australia's biodiversity.
72 species of seabird visit the State's coastal and oceanic waters, including gannets, shearwaters, giant-petrels and albatrosses.
16 species have been recorded breeding in South Australia, but only 10 of these breed here each year and in significant numbers.
Approximately 1.4 - 1.6 million pairs of seabirds breed in South Australia, about 1.3 million of these are migratory Short-tailed Shearwaters (or Muttonbirds) and White-faced Storm-Petrels.
Major potential threats to seabirds are likely to come from human disturbance at nesting sites, competition from commercial fisheries and habitat degradation through pollution or damage from other sources. Seabirds are therefore at greatest risk in Spencer Gulf and Gulf St Vincent, where most of the State's human population and industry are concentrated.

Threats to Seabirds

Small Population Size

Small population size and the associated probabilities of local colony extinctions are of concern for Fairy Terns, and may apply to some breeding sites for Caspian Terns and Pacific Gulls.

Pacific Gull Larus pacificus
(Photo: Tony Robinson)

Black-faced Cormorant Phalacrocorax fuscescens
(Photo: Peter Canty)

Disturbance to ground nesting birds can be caused unintentionally by inquisitive tourists and fishermen, or intentionally during acts of vandalism. Although examples may be isolated, disturbance may be a problem for species such as Fairy Terns because they occur in a small number of colonies.

Predation

Predation above 'natural' levels by feral animals (foxes, cats, dogs and rats) or by high numbers of Silver Gulls (for example, tern colonies at the Coorong).

Competition for Food

Competition for food particularly with commercial fisheries. Pilchard harvesting for the live-fishing bait and caged-tuna industries may be affecting terns, cormorants and penguins since pilchards are a very important dietary item for these birds.

Entanglement in Fishing Tackle

Drowning caused by entanglement in fishing tackle occurs frequently but to small numbers of individuals. Reported cases involve Little Penguins, Black-faced and Pied Cormorants. Dazzling by fishing night lights may be a problem for relatively small numbers of White-faced Storm-Petrels and Short-tailed Shearwaters.

Pollution

Pollution of the marine environment can cause both direct and indirect impacts on seabirds. These include: toxic spills (especially oil) which can kill or debilitate birds, bioaccumulation of pesticides and heavy metals, rubbish such as plastic bags and polystyrene which may be ingested by birds, eutrophication which causes seagrass dieback and algal blooms.

Actions Needed

Many gaps exist in the current database of information on South Australian seabirds. In general, better information on breeding numbers and sites is required for all species. This could be achieved by:

systematic, standardised survey and monitoring - particularly of Region 4 (Western Australian border to Cape Catastrophe)
diet studies - especially for species likely to be affected by the pilchard industry or a mass mortality of pilchards as occurred recently
monitor nest sites - of rare and uncommon species and colonies subject to repeated disturbance

Industry and community groups could undertake much of this, with a particular focus in gulf regions where hazards and risks to seabirds are greatest.

Short-tailed Shearwater Puffinus tenuirostris
(Photo: Steven Doyle)

Crested Tern Sterna bergii
(Photo: Peter Canty)

Regional Comparison

Refer to distribution map.

Region 1: Encounter Bay to Victorian Border

Seabird diversity and abundance are lowest in the inshore parts of this region because it is a relatively uniform high energy coastline and there is a paucity of suitable breeding sites.

Region 2: Kangaroo Island

Seabird diversity is relatively high in this region because of the diversity of low and high energy coastlines and the availability of numerous breeding sites, although overall abundance is low.

Region 3: The Gulfs

The largest number of seabird breeding species and breeding sites occur in the Gulf St Vincent and Spencer Gulf. Excluding the migratory Short-tailed Shearwaters and White-faced Storm-Petrels, the gulfs account for about 45% of the 286 - 315 colonies and 60% of the 113,000 to 193,000 breeding pairs of resident (as opposed to migratory) seabird species.

Region 4: Western Australian Border to Cape Catastrophe

The western region has the highest abundance of seabirds. About 75% of the pairs of breeding seabirds in South Australia are found on the coast between the Western Australian border and Cape Catastrophe. This is due to the 1.3 million migratory Short-tailed Shearwaters (or Muttonbirds) and White-faced Storm-Petrels which nest in burrows on islands primarily in this western part of the State. The shearwaters occur mainly off the west coast of Eyre Peninsula, the storm-petrels mainly in southern Spencer Gulf.

Species Summaries

More Information

Copley, P. B. (1996).The status of seabirds in South Australia. Pp. 139-180 in Ross, G. J. B., Weaver, K. and Greig, J. C. (eds) "The status of Australia's Seabirds: Proceedings of the National Seabird Workshop", Canberra, 1-2 November 1993. Biodiversity Group, Environment Australia: Canberra vii + 237pp.

Authors

Peter Copley, Senior Ecologist, Threatened Species, Department for Environment and Heritage
Julia Bolton, Wildlife Biologist

Contact

Peter Copley, Senior Ecologist, Threatened Species, Department for Environment and Heritage


	This page was last modified 2006-04-13