Red-tailed tropicbird (Phaethon rubricauda)

Description

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Red-tailed tropicbird fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Red-tailed tropicbird description

Named for its greatly elongated tail streamers, which are boldly coloured red and can measure up to 35 centimetres in length, the red-tailed tropicbird is a graceful seabird ^{(2) (3)}. The plumage is predominantly white, often with a pinkish sheen (the extent of which varies with region), except for a crescent of  black feathers in front of the eye and black streaks on the sides of the body and at the base of the wing ^{(4) (5) (6)}. Chicks hatch out covered in long, whitish to gray down, which moults to a juvenile plumage of white with heavy black barring on the head, back, and uppersides of the wings, before they develop the adult plumage ^{(2) (4) (6)}. This elegant bird has a robust, yet streamlined body with long, sharply-pointed wings that provide aerodynamic efficiency while soaring on thermals far out at sea, and a stout, downward-curving bill with serrated edges, used for holding onto slippery fish. While perfectly adapted for acrobatic aerial manoeuvres the red-tailed tropic bird is less impressive on land. The rearward-set legs and feet are set too far back to support the bird in an upright position, limiting movement on ground to an awkward shuffle ⁽⁵⁾.

Also known as

red-tailed bosunbird, silver bosunbird, strawtail.

French

Phaéton à queue rouge.

Size

Length: 78 – 81 cm ⁽²⁾

Wingspan: 104 – 119 cm ⁽²⁾

Weight

600 – 835 g ⁽²⁾

Red-tailed tropicbird biology

The tropicbirds can remain at sea for an indefinite time ^{(4) (5)}. These birds fly with rapid wing-beats and can also exploit their long wingspan and streamlined body shape to attain impressive altitudes by soaring upwards on rising thermals. While resting at sea, the tropicbirds float on the sea surface, due to their fully waterproof plumage, and will take to the air again after powerful beats of the wings and thrusts of the fully-webbed feet ⁽⁴⁾.

The red-tailed tropicbird feeds largely on flying fish and squid ^{(2) (4)}. Once prey is targeted, it hovers briefly in the air with the head and bill pointed downwards, before making a rapid, vertical, spiralling plunge into the water from 15 to 20 metres height ^{(2) (4) (5)}. In the water, this bird can make rapid movements, with quick turns and twists, using the half-bent wings to control its body, before capturing its prey in its serrated beak. Flying fish may also be caught in flight as they flee from feeding tuna below them, and the red-tailed tropicbird may seek out fish that have been flushed by boats or, more rarely, shoals of hunting tuna. On land, however, this bird is less impressive and movement is extremely awkward. The bird lies on its belly, pushes with its feet, and flops onto the belly again to make its way forward. At times it will even stab its bill into the ground to pull itself forward ⁽⁴⁾.

At sea, the red-tailed tropicbird is largely solitary, but during the breeding season they tend to nest in loose colonies ^{(2) (4) (5) (6)}. Prior to breeding, mature birds engage in unusual, aerial courtship displays, with up to 15 birds flying upwards in wide circles, all the while emitting harsh squawks, before monogamous partners pair up ^{(4) (6)}.  Nesting areas are defended against intruders and there may be fierce competition for the best nesting sites in a crowded colony where bloody fights between birds may ensue, with stabbing, slashing and the interlocking of bills ⁽⁴⁾. A nest scrape is created by the male on the ground under a bush or shrub that offers shelter from the sun ^{(2) (4) (5)}. A single egg is laid, and incubated alternately by the male and female for some 42 to 46 days. Once hatched, both adults feed the chick until it fledges at 67 to 91 days of age, with the length of time to fledging varying with the quantity of the food supply that year ^{(2) (6)}. During the non-breeding season juveniles and adults wander the ocean as far as 5,000 kilometres from their nesting colony ⁽²⁾. Birds first breed at 2 to 5 years of age and will return to the same colony to nest each year ⁽⁴⁾.

Red-tailed tropicbird range

The red-tailed tropicbird is a widespread seabird found across the tropical waters of the Indian and Pacific Oceans. It breeds on remote tropical islands in the southern Indian Ocean and between the Tropics of Cancer and Capricorn in the Pacific, as far east as the Hawaiian Islands, and also on the south-west Australian coast ^{(6) (7)}. Outside of the breeding season, the red-tailed tropicbird may travel as far north as Japan and as far south as New Zealand ⁽⁴⁾.

Red-tailed tropicbird habitat

The red-tailed tropicbird breeds on oceanic islands, where it nests on the ground beneath vegetation or in holes and crevices in inaccessible coastal cliffs ^{(3) (4)}. At sea, it forages widely over tropical pelagic waters, often far from the nesting site, where water temperatures are between 24 and 30 degrees Celsius ⁽⁶⁾.

Red-tailed tropicbird status

Classified as Least Concern (LC) on the the IUCN Red List ⁽¹⁾.

Red-tailed tropicbird threats

While the red-tailed tropicbird is not currently considered at risk of extinction, it has suffered extensively from human exploitation for food ^{(2) (7)}. This is a particularly significant problem on Christmas Island (Pacific Ocean), where the population was reduced from 3,000 in the 1960s to around 600 in 1998 and may go extinct in the near future as a result of continuing hunting ⁽⁴⁾. This ground-nesting bird has also suffered from predation by introduced rats, which eat eggs and small young, and rabbits which remove protective vegetation from nesting sites, and the population on Laysan Island may have gone extinct in the 1920s as a result of these threats ⁽²⁾. The red-tailed tropicbird may also be hunted on some South Pacific islands, where its tail streamers have ornamental uses, and is vulnerable to severe storms caused by the El Niño, which can cause partial or total breeding failure ^{(2) (4) (6)}.

Red-tailed tropicbird conservation

Although the red-tailed tropicbird is not thought to be the target of any specific conservation measures, it is found in a number of protected areas. Most colonies on the Hawaiian Islands are within reserves, and efforts have been undertaken to remove invasive predators and vegetation, and to limit disturbances ⁽⁴⁾. It is also protected by the African-Eurasian Waterbird Agreement, which encourages participating governments to develop conservation actions directed at migratory waterbirds and their habitats ⁽⁸⁾. The red-tailed tropicbird would benefit from further studies into its ecology, distribution at sea and abundance ⁽⁴⁾. 

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

Find out more

For more information on the red-tailed tropicbird and its conservation, see:

• BirdLife International:
  http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=3649&m=0

Authentication

Authenticated (31/10/2010) by Dr. E. A. Schreiber, Research Associate, Bird Department of the Smithsonian National Museum of Natural History.

Glossary

El Niño

A natural phenomenon that happens every 4 to 12 years, and lasts for several months, when upwelling of cold, nutrient-rich water does not occur. This causes the warming of ocean surface water across the central Pacific and off the western coast of South America and causes die-offs of plankton and fish. It also affects Pacific jet stream winds, altering storm tracks and creating unusual weather patterns in various parts of the world.

Incubate

To keep eggs warm so that development is possible.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Pelagic

In birds, applied to sea birds that come to land only to breed, and that spend the major part of their lives out at sea.

Thermals

Masses of heated air which rise to several thousand feet, and may be used by birds, insects and man to gain altitude and exploit higher altitude winds.

References

1. IUCN Red List (June, 2010)
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
3. Nelson, J.B. (2005) Pelicans, Cormorants, and their Relatives. The Pelecaniformes. Oxford University Press, Oxford.
4. Schreiber, E.A. and Schreiber, R.W. (2007) Red-tailed tropicbird (Phaethon rubricauda). Cornell Lab of Ornithology. Birds of North America Online.
5. Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
6. New South Wales Department of Environment, Climate Change and Water: Threatened Species Information (June, 2010)
   http://www.environment.nsw.gov.au/resources/nature/tsprofileRedtailedTropicbird.pdf
7. BirdLife International (June, 2010)
   http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=3649&m=0
8. African Eurasian Waterbird Agreement (June, 2010)
   http://www.unep-wcmc.org/