|
Ocean Watch Susan Scott |
Fairy terns are friendly
and loved on Tern IslandUsually when someone looks over my shoulder while I'm writing, my concentration flies right out the window. Here on Tern Island, however, it's the window itself causing the problem.
At this moment, two fairy terns stand on its louvered sill, reading over my shoulder.
OK, they aren't really looking at my computer screen, but still.
How can a person get any work done when the cutest, most sweet-tempered birds in the world sit not 2 feet from your chair?
Fairy terns, 12 inches long with a 28-inch wingspan, are the darlings of Tern Island, but they are not its namesake.
That honor goes to sooty terns, seabirds slightly larger than fairy terns that breed here by the thousands.
The black-and-white sooties are few people's favorites, because of their 24-hour-a-day screeching calls, but almost everyone loves the friendly fairies.
Their translucent, white wing feathers and big black eyes evoke images of angels, and they hover fearlessly around your head with Tinkerbell-like charm.
Another of fairy terns' intriguing qualities is their habit of laying their eggs in perilous places.
Right now on Tern Island, fairy tern eggs and chicks balance on bare branches, wobble on window ledges and teeter in tiny depressions of concrete blocks and posts.
Since such precarious positioning causes parents to lose many of their eggs and chicks, people love to root for them.
Approximately 500 to 750 pairs of fairy terns nest (using the term loosely) on this 36-acre island, and it gets crowded.
Tern families reside on and near most of the buildings here, including the concrete ledge around the base of the barracks.
Often, these attractive birds flutter up to the window sills and give us a thrill.
Tern eggs frequently fall to the ground, and if they don't, then the chicks often do.
Here on Tern Island, the reproductive success rate, meaning a chick that flies off the island, is a dismal 30 percent.
On Oahu, which offers more choice spots, the success rate is 76 percent.
When a pair of fairy terns lose an egg or chick, they try again, laying up to six eggs a year.
Super-successful couples can raise three offspring a year.
Since each one requires about four months' care, parenting for some terns is a year-round job.
Researchers speculate that this behavior is an adaptation to breeding on coral- or volcanic-rock islands where no nest material exists.
This specialization in balance enables fairy terns to colonize areas unsuitable to other tern species.
Marcy Okada, a volunteer biologist from Hawaii Kai, has had the discouraging job of monitoring the fairy terns here on Tern Island for the last four months.
This week, she found one of her chicks hanging upside-down by its feet on a branch. She righted it, but sadly, the next day it was gone.
Officially these seabirds are called white terns, but I find it hard to use that dull name. These window peepers will always be fairy terns to me.
See the Columnists section for some past articles.
Marine science writer Susan Scott can be reached at http://www.susanscott.net.
