(Common) white tern, Gygis alba (protonym, Sterna alba), also known as the manu-o-Kū, or the angel tern, white noddy, Atlantic white tern, and incorrectly (and confusingly) as the fairy tern (a common name that actually belongs to a different species, Sternula nereis), photographed at Waikiki, Oahu, Hawaii (USA).
Image: Mike Dunford, 19 July 2011 (with permission) [velociraptorize].
Canon EOS 60D, 105 mm, ISO: 100, f/7.1, 1/500 sec
Question: These Pacific Island mystery birds are famous for their peculiar nesting behaviours. What weird nesting behaviour do they have? Why do they show this strange behaviour? Can you identify this species?
Response: This is an adult pair of common white terns, Gygis alba, that nest on Waikiki, on the island of Oahu, Hawai'i. This small, monomorphic species has a large range that includes the Pacific and Indian Oceans, and it even nests on some Atlantic islands (hence, one of its alternate common names). These birds nest on coral islands, typically by balancing their egg on the fork of thin tree branches -- a behaviour that has made it famous (and which was indelibly stamped on my mind when I was very young and impressionable) -- but it also nests on rocky ledges and man-made structures. It is likely that this strange nesting behaviour evolved to reduce the numbers of ectoparasites that feasted on the defenseless nestlings.
Here's a video filmed on Sand Island (Midway Atoll) in 2009, of adult common white terns just ... sitting. I know, this sounds boring, but everything that these birds do -- yes, even sleeping! -- is cute beyond all description:
Did you see that bird calling in its sleep? Did you see those teeny-tiny webbed feet? Aren't they just cuuuute? Squeeeee!
Deep breath.
Okay, one more deep breath.
Here's a video of an adult with its chick filmed on Sand Island (Midway Atoll) in 2010. I have to warn those of you with easily-bled hearts that this video easily qualifies as cute overload, so view with extreme caution:
I am feeling weak all over after watching those two videos. If you are like me, you'll need to lie down for awhile to catch your breath. I've been informed that NHS thanks me to wait at least one week before sharing another squeee-inducing mystery bird with you.
You are invited to review all of the daily mystery birds by going to their dedicated graphic index page.
If you have bird images, video or mp3 files that you'd like to share with a large and (mostly) appreciative international audience here at The Guardian, feel free to contact me to learn more.
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