Seabirds

Red footed booby/ Sula sula / Family - Sulida

The Great Barrier Reef is home to approximately 215 species of birds, of which 29 are seabirds, attracted to the plentiful supply of food, mainly fish and squid. They are an important part of the marine environment.

Birds of the Great Barrier Reef can be divided into three main: landbirds, shorebirds and seabirds. In addition to the more common varieties such as gulls, cormorants, pelicans and terns, the reef is also home to less familiar species such as shearwaters, boobies, tropicbirds and frigatebirds.

Seabirds have a major influence on island ecosystems. Droppings from the birds (guano) fertilise plants and assist the introduction of plants on coral cays, while seeds that attach themselves to the feathers and feet of the birds are carried to new locations.

Habitat

Many of the species live and breed on continental islands and cays with 19 species of seabirds breeding on about 78 islands and cays. Many nest in shallow scrapes with little nesting material, while others prefer open areas, under vegetation, shrubs and trees.

Tropical petrels, storm petrels, prions, shearwaters, boobies and tropicbirds are found in offshore waters and at the outer edge of the Great Barrier Reef. These pelagic species are the true 'ocean wanderers.'

Inshore beaches, mudflats, estuaries and mangrove forests support a diverse population of resident land and shorebirds, as well as many migrating shorebirds (waders). These include pelicans, eastern reef egrets, silver gulls and cormorants.

Reproduction

Some birds require specific requirements for breeding and the sites vary. Breeding times and locations for different species vary throughout the year. Birds such as the shearwaters breed in summer along with most seabirds in the southern part of the reef. In the northern part of the reef breeding is not so rigid, with some tern species breeding all year round. Each species has a different location for breeding with some being faithful to their own sites returning each season. Other species move around, nesting on different islands.

Feeding

Seabirds feed on a variety of supplies found in many different locations along the reef. The following is a general list of foods taken by different groups:

Seabirds will drink fresh water if it is available in preference to salt water. Some seabirds have developed a salt water-excreting gland in the nose, which extracts the salt from the water and empties it back into the sea.

Threats

Great care should be taken when visiting known seabird breeding grounds. Walking or sitting carelessly can destroy eggs or chicks. Some birds are easily frightened and may abandon their eggs and chicks.

Apart from human disturbance, natural pressures such as storms and cyclones also affect seabird numbers. The effects of these natural events can be considerable, but can be tolerated because they are irregular. Unfortunately careless human activity is much more likely to delay or prevent a colony's recovery from natural disasters.

There are many ways we can protect birds and their habitats:

• During the breeding season, some islands of the Great Barrier Reef are closed to all visitors. For example, the Brook Islands are completely off limits during summer to protect the thousands of Pied Imperial Pigeons that migrate from Papua New Guinea to nest there.
• Special fire regimes are in place to manage vegetated islands and cays.
• Preservation of the mangrove forests is vital, not only for birds and other animals, but also to maintain the natural tidal flows and to offset the destructive effects of cyclones.
• Pollution control is necessary to protect the Reef from excessive sediment, rubbish and waste that affect critical mangrove, mudflat and inner reef habitats, and alter food supplies.
• Controlling feral animals will help to reduce predation on nesting birds and young.
• Control of introduced plants will allow native vegetation to regrow.
• Controlling beach access and vehicles on sand dunes will help to maintain these features and protect vulnerable ground-nesting birds. Dunes are a natural part of beaches and are our first line of defence from coastal erosion due to rising sea levels.