The puaiohi or small Kauai thrush is an endangered bird endemic to the island of Kauai, Hawaii. The sole population of about 500 birds is currently restricted to remote, high elevation areas of the Alakai Plateau. Puaiohi nest primarily on steep stream-side cliffs, and their distribution and abundance are limited partly by the availability of suitable nest sites. Invasive black rats often eat nesting adults, nestlings, and eggs, and ground-based rodent control has not been effective at reducing nest predation.
Researchers at the NWRC Hilo, Hawaii field station investigated whether artificial nest structures might be a viable alternative to rodent control by testing nest box designs to find one that was resistant to rats. In laboratory trials, three current nest-box designs for puaiohi were evaluated and found to not be rat resistant. From these initial results, researchers developed and tested an improved design.
“Captive rats were unable to enter the new nest box because of its overhanging entrance design,” notes NWRC’s Dr. William Pitt. Field tests of the new nest box design are currently underway to determine whether the boxes will be successfully used by wild birds.