54Wildlife Conservation Plan for Seabirds

54 Wildlife Conservation Plan for Seabirds

Invasive species, particularly rats and cats, have caused significant losses in Red-tailed Tropicbird colonies. The species has been shown to benefit from eradications that have been carried out to date. An increased frequency and intensity of tropical storm and cyclones may reduce breeding success. Sea level rise has the potential to eliminate breeding habitat on low lying islands and cays.

 Determine Red-tailed Tropicbird breeding population numbers and trends

 Manage human disturbance at breeding localities, particularly when adults are incubating eggs

 Control, or eradicate invasive species at breeding localities

 Implement best practice quarantine measures at breeding colonies to reduce the risk of any invasive species (re)establishing on islands

Photograph of a Red-tailed Tropicbird flying in blue sky and clouds

Wildlife Conservation Plan for Seabirds 55

White-tailed Tropicbird (Phaethon lepturus)

TABLE Species information for the Table White-tailed Tropicbird ((Phaethon lepturus)

The White-tailed Tropicbird (Phaethon lepturus) is a distinctive, medium sized white seabird with black diagonal bar on the inner upperwing, black based outer primaries and long white central tail feathers and yellow bill. It is much smaller than the Red-tailed Tropicbird. The species is pantropical, breeding at many locations, though usually in low numbers. Two subspecies occur in Australia, subspecies fulvus is listed endangered under the EPBC Act. The species is most common off North West Australia and a rare visitor to the Coral Sea and east coast. The species is primarily oceanic in tropical waters, rarely inshore, and only is near land when breeding. Nests are located on islands and atolls utilising a variety of habitats from closed canopy rainforest to bare sandy ground and rugged rocky terrain. The species feeds mainly on fish and cephalopods, captured by deep plunge diving. Patterns of movement away from the breeding sites is not well known.

The global population is estimated at >50,000 individuals (del Hoyo et al. 1992). The Australian population is poorly known owing to the numerous breeding sites and protracted and asynchronous breeding season making an accurate census difficult. The largest population breeds on Christmas Island (6,000–12,000 pairs; subspecies fulvus) and is believed to be in decline with additional breeding locations on Cocos (Keeling) Group and islands of Ashmore Reef Marine Park (subspecies lepturus).

Cyclones and tropical storms have been known to cause high levels of mortality of both chicks and brooding adults. Habitat affected by the storms may also render nesting sites temporarily unusable. The species readily adapts to artificial nesting sites and studies show that it can increase nesting success when compared to natural nests. Invasive species, particular rats and cats, have caused significant losses in White-tailed Tropicbird colonies. Invasive plants can render nest sites unsuitable. Tropicbirds are vulnerable to oil pollution at sea.