Monday, September 21, 2009

Eyes to the Skies: Phoenix Birds

Kate Madin, Woods Hole Oceanographic Institution
Steaming overnight from Enderbury Island, we arrived at 6am at Rawaki Island— in English called Phoenix Island, the namesake of the chain. As as we arrived we could see, hear, and smell the thousands of seabirds that nest here, since a layer of guano covers the coral rubble that makes up the island. These islands are resting and nesting places for many seabirds. Greg tells me that Rawaki is the most important island in the world for one highly endangered species, the Phoenix petrel.

The deep, navy blue of the open ocean grades into a clear blue over the reefs and a milky aquamarine in the shallows at water’s edge. On our arrival, groups went diving to check the reef, and ashore to survey the island.

The island is low and treeless, covered by grass and shrubs, about 1 mile long, with an extremely salty, ammonia-filled (from the guano) central lake. Rabbits introduced here in the past were a problem at the time of the last expedition here, overrunning the island and devouring vegetation. Kiribati began an eradication program, and the shore party wanted to find out if it was successful.

The shore party’s verdict: no rabbits and no rats — the eradication worked, and thousands of birds are the beneficiaries: boobies, frigate birds, terns, petrel, curlews, and more. Randi Rotjan captured an image of a fairy tern with a fish, and Greg Stone took these shots of a pair of Phoenix petrels, and an unlikely couple – a tropic bird and a young frigate bird, sharing a coral shelter.

The dive party’s view? Larry said, “It’s a beautiful reef, with long tongues of white sand bottom separating ridges of healthy coral with by colorful reef fish – but no big fish (such as trevally shown here) like we saw at other islands, and we saw no sharks.”

The good news is that there are larger live coral heads here than at other islands – large enough that coral biologist David Obura, aided by Larry and the ship captain Jonathan, was able to take a cylindrical core sample from one, brain coral, from the surface of the coral, down into skeleton it laid down in the past – for WHOI scientist Anne Cohen. The image, taken byLarry, shows David drilling the core.

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