(Editor’s Note: Alison Green, senior marine biologist at The Nature Conservancy, is spending the next two weeks diving and exploring Palmyra Atoll as part of the first marine assessment of the atoll. Follow her posts from Palmyra on Cool Green Science…and learn more about the expedition.)
When you land at Palmyra Atoll, one of the first things you notice is the outrageous number of seabirds.
Palmyra has the only land within 450,000 square miles of ocean, and provides critical nesting and feeding grounds for hundreds of thousands of birds.
Great and lesser frigate birds; brown, masked and red-footed boobies; white- and red-tailed tropic birds; sooty and white terns; and black and brown noddies — all forage over hundreds of square miles of ocean using the atoll as their home base.
Today, we spent the morning exploring the lagoons and viewing the birdlife. And what I saw was spectacular.
My favorite was the male frigate birds (like the one above) ostentatiously displaying their red neck pouches for the girls. How those huge birds fly with large red balloons attached to their necks I’ll never know.
Some species — such as red-footed boobies, white terns, and frigates — nest in native trees, particularly Pisonia grandis, Pandanus, Scaevola (Naupaka) and the tree Heliotrope (Tournefortia argentea). Other birds on the atoll — such as sooty terns (in the image directly above), red-tailed and white-tailed tropic birds, and brown and masked boobies — nest on the ground.
But while seabirds are thriving at Palmyra, there are some serious threats to their long-term survival. One of the biggest concerns is introduced species — especially rats.
Rats jumped ship onto the islands many years ago, and thought they’d died and gone to heaven! They eat seabird eggs and chicks, and they are a major threat to ground-nesting birds.
An introduced scale insect is also killing the native Pisonia trees, and non-native coconut palms are taking over in some areas, reducing habitat for tree-nesting birds.
The future of nesting seabirds at Palmyra depends on the ability of island managers to eradicate these introduced species.
(Images: Sooty terns nesting and male frigate bird courtship display. Credit: Kydd Pollock/TNC.)