page_title: Red-billed tropicbird
section_title: Breeding
hierarchical_section_title: Red-billed tropicbird / Behavior / Breeding
caption_attribution_description: English&#x3a;&#32; Egg of red-billed tropicbird Collection of Jacques Perrin de Brichambaut.Français&#x202f;&#x3a;&#32; Œuf de Phaéton éthéré Collection Jacques Perrin de Brichambaut.
context_page_description: The red-billed tropicbird is a tropicbird, one of three closely related species of seabird of tropical oceans. Superficially resembling a tern in appearance, it has mostly white plumage with some black markings on the wings and back, a black mask and, as its common name suggests, a red bill. Most adults have tail streamers that are about two times their body length, with those in males being generally longer than those in females. The red-billed tropicbird itself has three subspecies recognized, including the nominate. The subspecies mesonauta is distinguished from the nominate by the rosy tinge of its fresh plumage, and the subspecies indicus can be differentiated by its smaller size, more restricted mask, and more orange bill. This species ranges across the tropical Atlantic, eastern Pacific, and Indian Oceans. The nominate is found in the southern Atlantic Ocean, the subspecies indicus in the waters off of the Middle East and in the Indian Ocean, and the subspecies mesonauta in the eastern portions of both the Atlantic and the Pacific Oceans and in the Caribbean. It was one of the many species described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.
context_section_description: The red-billed tropicbird usually nests on isolated cliff faces, in loose colonies. It uses a simple scrape nest, located in a place it can easily take off from. The age of first breeding is usually five years, although this age is variable; a three-year-old tropicbird was once seen breeding. In some locations, breeding happens year-round, while in others, breeding occurs seasonally. For example, for islands in the California Current, breeding starts in November or December, while it occurs year round in the Galápagos. Breeding is influenced by the availability of food, with an increase in food generally causing an increase in breeding. Individually, this bird only breeds every nine to twelve months. A breeding bird usually returns to its partner and nest location from the previous breeding cycle.
  Courtship and pairing usually lasts three to five weeks, during which this bird performs aerial courtship displays to potential mates. The courtship displays include flying in the air which takes the form of gliding interspersed with short periods of rapid wing-beating. In one display, a pair glide together for 100–300 meters (330–980 ft), with one bird around 30 cm (12 in) above the other. The upper bird bends its wings down and the lower lifts its up, so they are almost touching. The two sink to about 6 meters (20 ft) above the sea before breaking off.
  At nest sites, battles sometimes occur between two or more pairs before the original owners declare themselves as the owner of the nest. Red-billed tropicbirds are aggressive at nest sites, fighting with each other and ousting species such as shearwaters, petrels, and white-tailed tropicbirds. They have also been recorded taking over nests of white-tailed tropicbirds and raising their young if they failed to destroy their eggs. Vagrant red-billed tropicbirds have been implicated in egg loss in red-tailed tropicbird nests in Hawaii.
  This tropicbird usually lays a clutch of one white buff to pale purple egg with reddish-brown spots. The egg usually measures 45 by 60 millimeters (1.8 by 2.4 in) and weighs around 67 grams (2.4 oz)—10% of the adult female's weight. It is incubated by both sexes for 42 to 46 days. If the egg does not survive the first few days in the nest, the female will usually lay a replacement egg. The chicks that hatch eventually fledge in about 10 to 15 weeks after hatching, although most fledge after about 80 to 90 days. Normally, the maximum weight of the chicks is about 725 grams (1.6 lb), but on years that are hotter than average, this can drop to about 600 grams (1.3 lb).
  Born helpless and unable to move around (nidicolous and semi-altricial), the chicks are constantly brooded by the parents until they are 3 to 5 days old, when they can thermoregulate their body temperature. They grow their first feathers—scapulars—at 13–15 days, followed by primaries at 24–27 days, tail feathers at 30–35 days and are fully feathered by 55 days. They are attended by the parents more between the 30th and 60th days; a behavior possibly related to the greater food requirements of the chicks during those days. Semi-digested food is regurgitated and then fed to younger birds, with older birds being fed solid food. The parents can be seen at normal rates with the chicks up to about the 70th day, after which the attendance by the parents falls rapidly. Chicks receive no care after fledging, with only about one out of seven chicks receiving food after the 80th day, and almost no chicks are visited after about 90 days. After fledging, the chicks will leave the nest, with few remaining after about 100 days.
caption: Red-billed tropicbird egg
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "240", "Image YResolution": "240", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS6 (Windows)", "Image DateTime": "2018:02:01 13:57:57", "Image ExifOffset": "2248", "Image XPKeywords": "[69, 0, 114, 0, 99, 0, 233, 0, 0, 0]", "Image Padding": "[]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "4468", "Thumbnail JPEGInterchangeFormatLength": "5086", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "3496", "EXIF ExifImageLength": "3496", "EXIF Padding": "[]"}