The Magnificent Frigatebird is one of the most well-known seabirds throughout the American tropics. Most recognize this species for the inflatable red gular sac shown on adult males but their remarkably long wings, forked tail, and piratical lifestyle make this species an incredible sight no matter what age or sex. In fact, frigatebirds have the longest wings compared to body weight of any species of bird!
I was fortunate to spend a few hours at Fort Jefferson in the Dry Tortugas National Park back in early March, where the local breeding population of frigatebirds is quite cooperative for photography. The Dry Tortugas is home to the only breeding location for this species in the United States, although they breed throughout the Caribbean and Central and South America. Prior to this visit, the closest I had ever been to this species was while driving down Route 1 through the Florida Keys and having an occasional flyover, but never had I seen them as close as they are at Fort Jefferson – sometimes flying so low over the island that I had trouble fitting the entire bird within my camera frame!
Frigatebirds are actually the only family of seabirds who have fairly obvious plumage differences between male and female, as well as having a distinct immature plumage. The adult male Magnificent Frigatebird is glossy-black on both its upperside and underside, with a hint of purple and green on its back. During the breeding season, the adult male’s gular sac is bright red in color and is quite noticeable, even when not inflated. During the non-breeding season the male’s gular sac is an orange or yellow color.
The adult female is similar to the adult male, but has a white breast and black belly. Females and immatures, of course, lack a gular sac. Immature frigatebirds remain in their juvenile plumage for 4 to 6 years and then molt into their respective adult plumage type. The immature frigatebird is similar to the adult female, but the white on their undersides extends to their belly. Immatures also have a white head and shown a brownish tinge to their upperwings.
Despite being a seabird, the frigatebird does not have a protective waterproof coating on its feathers, and so cannot actually dive to catch fish for itself. Instead, the frigatebird either plucks prey from the surface of the water with its long bill or takes on a more aggressive approach at securing a meal. The Magnificent Frigatebird is kleptoparasitic, meaning that it is very willing and able to chase down and steal food from other seabirds such as terns, gulls, and tropicbirds. The frigates will ruthlessly terrorize another bird for its food until the smaller bird either drops or regurgitates its meal, allowing the frigatebird to snatch the food out of the air. I don’t know about you but if I were something like a Royal Tern with a recently-caught fish and saw a group of frigatebirds coming towards me, like in the photo below, I would probably throw up too.
Alex is currently studying Wildlife Biology at the Pennsylvania State University. Alex is a traveling field ornithologist, most recently working for the Center for Conservation Biology, studying migrant Whimbrel and other coastal birds of Virginia's Eastern Shore. He has done field work across the US on everything from Yellow-billed Cuckoos to Long-billed Curlews.
An avid birder since 8 years old, Alex has since been able to travel not only across most of the United States, but also to Central America and Southern Africa in search birds. Raptors, shorebirds, and warblers are among his favorite groups of birds to observe and photograph.
Alex is obsessive about eBird, combing through the data to help out with Big Days and is also a budding wildlife photographer.