Magnificent Frigatebird Life History

Habitat

Habitat Oceans

Magnificent Frigatebirds range along coasts and islands in tropical and subtropical waters. They nest and roost in mangrove cays on coral reefs and in low trees and shrubs on islands. Magnificent Frigatebirds forage over warm oceans far out to sea, along the coast, and in shallow lagoons.

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Food

Food Fish

Magnificent Frigatebirds eat primarily flying fish, tuna, herring, and squid, which they grab from the surface of the water without getting wet. They also eat plankton, crabs, jellyfish, and other items on the surface of the water including discarded fish from fishing boats. Magnificent Frigatebirds forage for themselves, but they also chase and harass other seabirds and frigatebirds forcing them to regurgitate recently captured meals, swooping down to steal the meal before it hits the water.

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Nesting

Nest Placement

Nest Shrub

Magnificent Frigatebirds nests in dense colonies on top of low trees and shrubs on islands. Nests are packed into small areas and are often within striking distance of another nest. The female builds the nest on the display perch used by the male she chooses.

Nest Description

The male brings sticks to the female, which she arranges into a flimsy platform about 9-14 inches wide. The male gathers sticks from trees and shrubs, but also steals them from other males. Nest building takes about 13 days.

Nesting Facts
Clutch Size:1 egg
Number of Broods:1 brood
Egg Length:2.6-2.9 in (6.5-7.4 cm)
Egg Width:1.7-2.0 in (4.4-5 cm)
Incubation Period:53-61 days
Nestling Period:150-185 days
Egg Description:White.
Condition at Hatching:Naked and helpless.
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Behavior

Behavior Soaring (seabird)

Frigatebirds soar effortlessly over the ocean rarely flapping their long, pterodactyl-like wings and using the long tail to steer. Though they are frequently seen soaring, they are masters of pursuit. They chase other birds including frigatebirds, forcing them to regurgitate their recent meal, which they scoop up before it hits the water. Their gracefulness ends as soon as they head towards land, where they awkwardly perch in low shrubs and trees. Their strong toes help them hold onto branches, posts, and boat masts, but their small feet in combination with their short legs makes it nearly impossible for them to walk on land. On land, males often flutter the balloonlike throat sac (or "gular pouch") to cool off. Males and females also regulate their body temperature by holding up their wings up to sun themselves. To get airborne, they flap a few times and use the wind to help lift them into the air. Male Magnificent Frigatebirds gather in groups to court females. They perch in low trees and shrubs with their red throat sac inflated like a balloon and clatter their bills, waving their heads back and forth, and calling at females flying overhead. Females choose a mate and begin building a nest on the male's display perch. The pair stays together for up to 3 months, after which the male leaves and the female raises the chick alone for up to 1 year.

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Conservation

Conservation Restricted Range

Magnificent Frigatebirds are relatively common, but Partners in Flight lists them as Yellow Watch List species due to declining populations in the Americas. Magnificent Frigatebirds rate a 16 out of 20 on Partners in Flight Continental Concern Score. The estimated global population is 59,000-71,000 breeding pairs. In areas where they breed, many populations are declining due to urban and resort development. Several islands in the Caribbean, including Marquesas Keys off of southern Florida, Aruba, and Seal Key in the Bahamas, no longer support breeding colonies following coastal development. Overfishing, predator introductions on nesting islands, and hurricanes may also reduce nesting success.

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Credits

Diamond, Antony W. and Elizabeth A. Schreiber. 2002. Magnificent Frigatebird (Fregata magnificens), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA. 

Lutmerding, J. A. and A. S. Love (2016). Longevity records of North American birds. Version 2016.1. Patuxent Wildlife Research Center, Bird Banding Laboratory, Laurel, MD, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

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