Red-tailed tropicbird

Red-tailed tropicbird
DickDaniels (http://theworldbirds.org/) · CC BY-SA 3.0 · source
Name	Red-tailed tropicbird
Status	LC
Status system	IUCN3.1
Genus	Phaethon
Species	rubricauda
Authority	(Gmelin, 1789)

Red-tailed tropicbird is a seabird in the family Phaethontidae known for long tail streamers and white plumage with reddish tail feathers. It breeds on tropical and subtropical oceanic islands across the Indo-Pacific and occasionally in the eastern Pacific, where it nests on cliffs and isolated islets. The species is a pelagic forager, associated with surface-feeding fish and squid, and has been the subject of studies by ornithologists and conservation organizations.

Taxonomy and systematics

The species was described in the 18th century and placed in the genus Phaethon alongside related tropicbirds; early describers included Johann Friedrich Gmelin and collectors working with contemporaries like Georges Cuvier and Joseph Banks. Molecular phylogenetics comparing mitochondrial markers and nuclear loci have been conducted by researchers affiliated with institutions such as Smithsonian Institution, Natural History Museum, London, and University of California, Berkeley to resolve relationships among Phaethontidae, Procellariidae, and Sulidae. Subspecies delineation has been debated in literature published in journals linked to societies like the American Ornithological Society and the British Ornithologists' Union, with regional populations in archipelagos studied by field teams from organizations including BirdLife International and regional conservation NGOs.

Description

Adults exhibit predominantly white plumage with elongated central rectrices forming tail streamers and conspicuous rufous to crimson tail markings. Morphometric measurements have been recorded in field guides produced by Cornell Lab of Ornithology and the Royal Society for the Protection of Birds, detailing wing chord, bill length, and body mass. The species shows sexual monomorphism similar to descriptions in works by John James Audubon and measurement comparisons with Francesco Redi-era catalogs; plumage variation has been photographed in surveys by expeditions from the Australian Museum and the Bishop Museum. Juvenile plumage and molt sequences are described in monographs used by researchers at Monash University and the University of Auckland.

Distribution and habitat

The species breeds on islands across the central and western Indo-Pacific, with colonies recorded on island groups such as Hawaii, Galápagos Islands, Cocos (Keeling) Islands, Christmas Island (Indian Ocean), Chagos Archipelago, and archipelagos near Australia and Fiji. At-sea distributions have been mapped in collaboration with oceanographic programs at Woods Hole Oceanographic Institution and Scripps Institution of Oceanography, linking occurrences to currents like the Equatorial Counter Current and features tracked by the National Oceanic and Atmospheric Administration. Breeding sites are typically on predator-free islets, sea cliffs, and lava flows noted in surveys supported by Conservation International and regional agencies such as Department of Conservation (New Zealand). Seasonal movements and vagrancy have brought individuals to coasts of Japan, Mexico, and the United States territories; ring-recovery studies have been coordinated with the International Council for Bird Preservation frameworks.

Behavior and ecology

The species forages by plunge-diving and surface-seizing, following flotsam and associations with predators like Epinephelus groupers and dolphins, as documented in field studies by teams from University of Hawaii at Mānoa and the Australian National University. Diet analyses in peer-reviewed studies from institutions such as Tokyo University of Marine Science and Technology show fish and cephalopods dominate prey items. Social behavior at colonies includes aerial displays and vocalizations recorded and archived by researchers at Macquarie University and the Bishop Museum sound collections. At-sea movement and foraging ranges have been tracked using telemetry devices developed by collaborators at Massachusetts Institute of Technology and Deutsches Zentrum für Luft- und Raumfahrt projects. Interactions with invasive species and competition with burrow-nesting seabirds like those studied by RSPB and BirdLife International influence local ecology.

Reproduction and life cycle

Breeding seasons vary regionally, with colonies timing nesting to local resource peaks documented by survey teams from University of Queensland and Hokkaido University. The species lays a single egg in simple scrapes or crevices on bare substrate, a trait discussed in breeding manuals produced by Royal Society for the Protection of Birds and field guides from Cornell Lab of Ornithology. Both parents provision the chick; growth rates and fledging periods have been quantified in longitudinal studies by researchers at University of Cambridge and University of Oxford. Longevity estimates derive from banding records held in databases maintained by BirdLife International and national ringing schemes such as those run by Australian Bird and Bat Banding Scheme. Nest site fidelity and mate choice have been topics of behavioral ecology papers published in journals associated with the Linnean Society of London.

Conservation status and threats

Assessed as Least Concern by the IUCN on a global basis, the species faces localized threats including habitat loss from invasive mammals (rats, cats), light pollution near islands cataloged by International Dark-Sky Association studies, and bycatch in regional fisheries monitored by Food and Agriculture Organization of the United Nations programs. Conservation actions have been implemented through partnerships among BirdLife International, regional governments such as Government of Australia and Government of Kiribati, and NGOs including The Nature Conservancy to remove invasive predators and protect breeding islets. Climate change impacts, sea-level rise projections from Intergovernmental Panel on Climate Change, and increasing storm frequency pose emerging risks highlighted in reports by United Nations Environment Programme and marine research centers like Plymouth Marine Laboratory. Continued monitoring by research institutions and conservation bodies is recommended to track population trends and mitigate threats.

Category:Seabirds