Magnificent frigatebirds live along American, tropical coastlines. They breed as far north as 25 degrees north latitude in Mexico and Florida and as far south 27 degrees south latitude in Brazil. They are especially common in southern Florida, the Gulf Coast, the Caribbean islands and the west coast of Mexico.

Biogeographic Regions: nearctic (Native )

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDS: Pacific coast from Baja California to Ecuador; Atlantic-Caribbean region from Bahamas to Brazil and Cape Verde Islands, including Marquesas Keys (Florida), Texas coast (listed in AOU [1983] but not in Spendelow and Patton 1988), and the Antilles (including Isla Monito [Puerto Rico], and Tobago, Anegada, and George Dog [Virgin Islands]). Ranges at sea along Pacific coast from northern California south to northern Peru; throughout Gulf of Mexico, Caribbean Sea, and western Atlantic from North Carolina south to northern Argentina; in eastern Atlantic in vicinity of Cape Verde Islands; casually elsewhere (AOU 1983). In winter in the U.S., occurs mainly in Florida (especially Vero Beach area) (Root 1988).

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Male magnificent frigatebirds are entirely black except for brown inner secondaries on the upper wing and the presence of a red inflatable throat pouch called a gular sac. They also have faint purple gloss on the head and green on the neck, scapulars, and upper wing. Their legs and feet appear back or grayish. Females are also entirely black with a white chest and white and tan markings on the wings. Their legs and feet are flesh-colored or pink, and they lack a gular sac. Females are, in general, 15% larger than males. Immature magnificent frigatebirds have a white head and chest while the rest of the body is black. Their legs, feet, and bill are light-bluish gray.

Their large heads, long, pointed, narrow wings, and forked tails make them easy to distinguish even from a distance. They are most often seen soaring along coastlines at higher altitudes and their silhouette is readily recognizable. They are also recognizable by their large size and long, hooked bill. They have short legs and small feet not well-suited to walking or swimming.

Range mass: 1360 to 1815 g.

Range length: 100 to 230 cm.

Range wingspan: 90 to 230 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger; sexes colored or patterned differently; male more colorful; ornamentation

Length: 102 cm

Weight: 1667 grams

• Terrestrial
• Marine

Magnificent frigatebirds usually build their nests out of twigs on or around low-lying vegetation. Males gather twigs and other nest building materials while females remain at the males' display site and build the nest there. Nests are primarily constructed at ground level, but sometimes in trees as well. Nests are flat or slightly hollow with a diameter of 25 - 35 cm. They are usually fully exposed to the sun for the birds' sunning habits. A colony of magnificent frigatebirds can occupy about 500 m of shoreline with a total area of about 22,500 m squared. A colony with about 2500 pairs of birds in Barbuda, a small island in the Caribbean, is the largest known colony.

Habitat Regions: tropical ; terrestrial ; saltwater or marine

Aquatic Biomes: coastal

Other Habitat Features: estuarine

Comments: Mainly in coastal waters (sometimes inland over large bodies of water or in association with storms); generally within sight of land when offshore (Palmer 1962). Roosts on rocks, vegetation of offshore islands, and on rigging of boats (Stiles and Skutch 1989). Nests on islands in mangroves, low trees, and shrubs; usually on steep slope of offshore island (Stiles and Skutch 1989). Sensitive to disturbance; usually nests on most remote cays and islets (Raffaele 1983).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Generally stays within breeding range but may wander widely after breeding (Palmer 1962).

Magnificent frigatebirds eat mainly fish, as well as squid, jellyfish, and crustaceans. However, their diet can greatly vary due to food availability and preferred hunting technique. The three main hunting techniques are dipping, kleptoparasitism, and opportunistic feeding. When dipping, these birds gracefully glide just above the surface of the water and skim the surface with their beak to catch fish. However, they are only able to dip about 15 cm deep to avoid getting their feathers wet. Kleptoparasitism, the stealing of another animal’s food, is how this species gets one of their nicknames, "Man-'o-War". They chase other birds, particularly gulls, gannets, terns, and boobies. This chase continues until the victim is forced to disgorge their food. Magnificent frigatebirds then catch the disgorged food in mid air. They may also catch the other bird by the tail feathers and shake it until they release their food. Opportunistic feeding involves eating garbage, young turtles at hatching, and otherwise taking advantage of all available food sources. Magnificent frigatebirds eat fish scraps discarded by boats, offal (discarded parts of animals unfit for consumption) from slaughterhouses, and other garbage. Occasionally they steal food from the hands of humans. Females consume more than males because of their larger size and greater contribution to the feeding of hatchlings.

Animal Foods: fish; mollusks; aquatic crustaceans; cnidarians

Primary Diet: carnivore (Piscivore )

Comments: Eats mainly fishes caught on or near surface of water as bird flies or robbed from sea birds (e.g., boobies). Also eats jellyfishes, squids, and other marine animals of appropriate size. Major predator on hatchling sea turtles (Costa Rica, Stiles and Skutch 1989). Eats refuse discarded from fishing boats.

Magnificent frigatebird feeding habits affect their fish prey, especially flying fish (Exocoetidae), as well as some squid and crustaceans. Other birds like pelicans, gulls, gannets, terns, and boobies are affected by magnificent frigatebird kleptoparasitism. Magnificent frigatebirds are often found near groups of dolphins, tuna, or other predatory fish that drive much of their prey to the surface of the water. This makes magnificent frigatebirds more successful when using a dipping hunting technique.

There are no known birds that prey on magnificent frigatebirds. Mammals may sometimes take eggs and nestlings. However, magnificent frigatebirds closely monitor their eggs and hatchlings until they are fairly able to defend themselves and breeding occurs in colonies, where many eyes can keep watch for predators.

Magnificent frigatebirds are usually silent, but they do vocalize when approaching a colony, when begging for food (hatchlings), and during mating displays. Little is known about communication among frigatebirds.

Communication Channels: visual ; acoustic

Comments: Generally inactive at night but may fly after dark (Palmer 1962).

While there is little data on magnificent frigatebird lifespan, it is estimated at 30 years. Besides natural death, mortality is occasionally caused by destructive hurricanes and man-made interferences in colonies.

Average lifespan

Status: wild: 174 months.

During the breeding season, male magnificent frigatebirds congregate at male display sites. They inflate their large, red, gular sacs. These sacs, while inflated, can get so large that they obscure the bird's head. Males rapidly vibrate their wings and sit back on their tails. They stretch their wings out and throw their heads back for maximum display of the gular sac. Females then inspect the males. As females attempt to find a preferred mate, males twist and bend to make their gular sac look as large a possible, they also make a loud, drumming noise during this display. Magnificent frigatebirds form monogamous pairs each breeding season once females have selected mates. However, they rarely maintain the same partner from season to season.

Mating System: monogamous

Female magnificent frigatebirds lay a single egg three to four weeks after the beginning of breeding season. The incubation period for this species is not recorded, but has been estimated at 50 days. Because female parent involvement continues for much longer than male parental involvement, females only mate every other year. Males rarely care for their young longer than six months and breed annually. Juveniles near mature mass before fledging. Age of sexual maturity is not known but none breed until plumage is in mature phase.

Breeding interval: Female magnificent frigatebirds breed biannually, males attempt to breed annually.

Breeding season: Magnificent frigatebirds lay their eggs between mid-December and early April.

Range eggs per season: 1 (high) .

Average eggs per season: 1.

Average time to hatching: 50 days.

Range fledging age: 120 to 200 days.

Range time to independence: 21 to 24 months.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Average time to hatching: 50 days.

Average eggs per season: 1.

A magnificent frigatebird's egg is almost never exposed, being nearly continuously monitored by a parent. Hatchlings are altrical and are usually protected beneath a brooding parent. After about three weeks they are left alone in the nest for approximately half of daylight hours as parent birds search for food. Both parents contribute to provisioning hatchlings, but males contribute less than 40% of feeding. Around the sixth week the hatchling is substantially developed and can defend itself. At about the eleventh week, the male parent abandons the nest, leaving remaining parenting to the female. Females then compensate by nearly doubling the food provided for the hatchling. Females continue to feed hatchlings until they fledge and leave the nest. Often involvement continues after fledging, up to approximately four months.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female); pre-independence (Provisioning: Female)

Laying peaks from late October to mid-December in Puerto Rico (Kepler 1978). In Baja California, hatching peaked at weeks 7, 12, 17.5, and 23.3 of the calendar year (Carmona et al. 1995, Wilson Bulletin 107:328-337). Low reproductive rate. Clutch size usually is 1. Incubation, by both sexes, lasts 50 days or more. Young initially are tended by both sexes, first fly at about 150-210 days. First breeding may occur at age of at least 5-7 years. In Baja California, 46% of eggs or chicks died at some stage of development (Carmona et al. 1995, loc. cit.).

There are an estimated 50,000 to 71,000 breeding pairs of magnificent frigatebirds. Their numbers are apparently declining, due to human disturbances to nesting areas. There is a need for more research and protection plans in order to ensure that magnificent frigatebird populations remain stable. Regulations have been proposed to the Government of Antigua and Barbuda, but there is no current legal protection for this species.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: NNRB,N4N : NNRB: Unranked - Breeding, N4N: Apparently Secure - Nonbreeding

Rounded Global Status Rank: G5 - Secure

Comments: In Puerto Rico, human disturbance has eliminated some breeding colonies (La Parguera, Mona, Desecheo) (Kepler 1978, Raffaele 1983).

There are no known negative impacts of magnificent frigatebirds on humans.

Magnificent frigatebirds are beautiful and may attract ecotourism. They are also important members of the healthy ecosystems they inhabit.

Positive Impacts: ecotourism