Of the five extant species of frigatebirds, two are found on the Galapagos Islands: the great frigatebird and the magnificent frigatebird. They coexist on the archipelago and share many similarities — and just enough differences to tell them apart.
Great and magnificent frigatebirds are very similar in appearance. The magnificent frigatebird is slightly larger than the great frigatebird, but both have dark plumage that, from afar at least, makes them hard to separate. Look closer at the males, however, and you’ll see a notable difference in sheen: male great frigatebirds have a green sheen and male magnificents have a purple sheen.
One obvious and quite peculiar feature shared by males of both species is the red gular pouch on their throats (females have white throats). They use this during their elaborate mating rituals, during which they point their bills to the sky, inflate their red throat pouches and vibrate their outstretched wings to attract passing females.
When they’re not breeding or nesting, both species spend most of their time in the air. They are magnificently agile fliers, and can stay in the air for weeks at a time when necessary. When they hunt, they dive down to catch flying fish in the air, or use their long, hooked bills to snatch small fish and squid from the surface.
Unlike other birds found on the Galapagos, they cannot dive below the surface, and even landing on the water is dangerous. This is because frigatebirds produce very little oil from their uropygial glands, meaning their feathers become waterlogged and ineffectual when they are exposed to water.
The frigatebirds also use another tactic when hunting, albeit one that’s not particularly endearing. Both species are known to engage in kleptoparasitism, the act of chasing other seabirds, including boobies and tropicbirds, in order to force them to regurgitate their food. This act of airborne bullying has given rise to a common nickname: the “pirate bird.”
Read more about the Magnificent Frigatebird at Galapagos Conservation Trust.
Other Galapagos Wildlife