Christmas Island frigatebird, Fregata andrewsi, also known as the Christmas frigatebird, Andrews' frigatebird or Andrews's Man-o'-War, photographed flying over the Indian Ocean.
Image: David Boyle/National Geographic [velociraptorize].
Question: This lovely mystery bird wanders throughout tropical and subtropical south seas when not nesting. Can you name the species and tell me where it nests?
Response: This is a Christmas Island frigatebird, Fregata andrewsi. It appears to be an immature bird based on its blue coloured bill, brown head and brown appearing throughout its dark plumage.
This species is larger than even the greater frigatebird, Fregata minor but is distinguishable by the white belly and collar of the adult female and white belly of the adult male, and by the pale bars outer parts of the upperwing. (I know, stupid scientific name for the greater frigatebird, but that's another story for another day.)
Christmas Island is blasted by cyclones or severe storms every five to ten years. Chance events such as severe storms could have severe effects on the global population of the Christmas Island frigatebird because of the birds' small population size and extremely limited breeding distribution.
But that said, the most serious threat to the Christmas Island frigatebird is the introduced yellow crazy ant, Anoplolepis gracilipes. These insects already occupy 15 to 18% of the area of Christmas Island, and is probably still spreading. The yellow crazy ant, listed as one of the 100 most devastating invasive species in the world, has the potential to not only prey on nestlings, but also to alter the whole ecology of the island. It is not known if the yellow crazy ant has reached the Christmas Island frigatebird nesting colonies at this time (but it is known to have significantly reduced the population of the endemic red ground crab, Gecarcoidea natalis, a keystone species on this island).
You are invited to review all of the daily mystery birds by going to their dedicated graphic index page.
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