Boobies

Booby/ Sula sp. / Family - Sulidae

Boobies are large seabirds, related to gannets, that dive from heights of up to 30m to catch fish.

Boobies have also been seen perched on ships at sea, using the ship as a vantage point to dive on flying fish skipping away from the bow wave.

The booby has a cigar like body, long narrow wings, thick white down, conical bills and wedge-shaped tails. The nostrils are externally closed, with breathing at each side within the bill. Air sacs are located under the feathers of the throat and breast to cushion the impact of the dive.

Habitat

Bobbies often nest in large colonies and in often close together on level ground, cliff tops, cliff ledges, bushes or treetops.

Reproduction

Nests vary from piles of seaweed, debris on the ground to substantial stick nests in trees.

Boobies lay two eggs, but usually only hatch one chick. During incubation, which is shared by both parents, eggs are kept warm by the webs of the feet that cover them. Incubation takes 42-47 days. The chicks hatch naked and dark skinned and after about a week grow a thick white down. The maturing period varies from 10 to 17 weeks depending on the species and the varying food supply.

Both parents feed the young chicks by regurgitating food from the gullet. The chicks become very large and fat but starve for a week before leaving the nest.

Boobies are frequently pirated by frigatebirds.

Feeding

Fish are the boobys' primary diet, and these are usually caught by diving. However, boobies also catch flying fish skipping away from the bow wave of ships.

Threats

Great care should be taken when visiting known breeding grounds for seabirds. 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.