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Christmas Island White-tailed Tropicbird (Phaethon lepturus fulvus)

The golden bosun is a subspecies of White-tailed Tropicbird endemic to Christmas Island. It nests in forest, cliffs and other sites across the island, and forages in warm waters off the coast.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Seasonal planning

Breeding occurs throughout the year on Christmas Island.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Year-round breeding: Breeding occurs throughout the year on Christmas Island.

Identification: Appearance

Many birds have a golden wash to their plumage, although white-morph birds also occur on Christmas Island. The form is also known locally as the golden bosun.

Many birds have a golden wash to their plumage, although white-morph birds also occur on Christmas Island. The form is also known locally as the golden bosun.

Identification: Confirming identity

Confirm the identity of any suspected record with a specialist and a photograph or voucher, as required by the relevant permit.

Distribution: Known range

This subspecies is endemic to Christmas Island, where it nests across the island and feeds in warm waters off the coast.

This subspecies is endemic to Christmas Island, where it nests across the island and feeds in warm waters off the coast.

Distribution: National mapping

The Commonwealth species distribution model (SNES) maps where the species or its habitat is known, likely or may occur. Use it with local records and site inspection.

Habitat: Habitat

It nests primarily in forested parts of Christmas Island, but nesting sites also include rainforest trees, sandy ground and rocky areas such as cliffs and quarries. It forages in warm waters off the coast.

It nests primarily in forested parts of Christmas Island, but nesting sites also include rainforest trees, sandy ground and rocky areas such as cliffs and quarries. It forages in warm waters off the coast.

Foraging habitat: Diet

Golden bosuns forage at sea, diving for fish and squid. The subspecies is also reported to feed on marine molluscs.

Golden bosuns forage at sea, diving for fish and squid. The subspecies is also reported to feed on marine molluscs.

Breeding habitat: Breeding

It breeds throughout the year on Christmas Island and lays a single egg. Nest sites include rock crevices and hollows in rainforest trees, as well as other sites across the island.

It breeds throughout the year on Christmas Island and lays a single egg. Nest sites include rock crevices and hollows in rainforest trees, as well as other sites across the island.

Sheltering habitat: Shelter

It roosts at sea; only adults incubating or brooding remain on nests at night.

It roosts at sea; only adults incubating or brooding remain on nests at night.

Threats: Threats

Reported pressures on tropicbirds include habitat loss and human disturbance. Introduced rats are also reported to take eggs and kill birds.

Reported pressures on tropicbirds include habitat loss and human disturbance. Introduced rats are also reported to take eggs and kill birds.

Threats: Works risk

Clearing or construction that removes nesting habitat, including forest, cliff or ground sites, could affect the subspecies. Disturbance around nesting areas may also be harmful.

Survey methodology: 1. Commonwealth guidance

Use methods consistent with the Commonwealth survey guidelines and engage a specialist with the right permits.

For EPBC Act referrals, survey effort and methods should be consistent with the survey guidelines for Australia's threatened birds, read with the Significant impact guidelines 1.1.

Survey methodology: 2. Limits

A non-detection is not proof of absence. Match survey timing to the species and season, and record effort.

Vegetation associations: Rainforest or vine thicket

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

It nests primarily in forested parts of Christmas Island, but nesting sites also include rainforest trees, sandy ground and rocky areas such as cliffs and quarries.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: not specified.

Habitat use: general

Ecosystem associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific ecosystem association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Soil and substrate associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific soil association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Water and wetland associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific water association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before disturbance: 1. Desktop and approvals

Confirm whether the project could affect the species before works begin.

Check national mapping, state records and recent surveys for the site. An action likely to have a significant impact on this nationally listed species needs EPBC Act referral, and state permits apply where it is state listed.

Before disturbance: 2. Plan to avoid

Plan in-water works, vessel movements and lighting to avoid known habitat and sensitive periods, and set observer and shutdown procedures before works start.

During disturbance: 1. Controls

Keep works inside the approved footprint and conditions.

Use spotters and exclusion zones for in-water works and vessels, and pause works if the species is seen within the zone.

During disturbance: 2. Stop and report

If the species is found unexpectedly, stop work at that spot and contact the project ecologist and the relevant agency.

After disturbance: 1. Records

Record outcomes.

Record sightings, habitat lost or retained and any injury or death, and report them under the approval conditions.

Rehabilitation: 1. Restore

Restore disturbed habitat where possible.

Remove temporary structures, restore natural flow and substrate, and monitor water quality until it returns to baseline.

Sources