Micronesica 32(2):181-190, 2000 Population status of the Tinian Monarch (Monarcha takatsukasae) on Tinian, Commonwealth of the Northern Mariana Islands MICHAEL LUSK 1 U.S. Fish and Wildlife Service, Pacific Islands Ecoregion, 300 Ala Moana Blvd., Room 3108, Box 50088, Honolulu, HI 96850 STEVE HESS 2 , MICHELLE REYNOLDS U.S. Geological Survey, Biological Resources Division, P.O. Box 44, Hawaii National Park, HI 96718. SCOTT JOHNSTON 3 U.S. Fish and Wildlife Service, Pacific Islands Ecoregion, 300 Ala Moana Blvd., Room 3108, Box 50088, Honolulu, HI 96850 Abstract—We conducted surveys to evaluate the current population sta- tus of the Tinian Monarch (Monarcha takatsukasae), an insectivorous forest bird restricted to the island of Tinian, Commonwealth of the Northern Mariana Islands. In 1996, we recounted transects surveyed in 1982 and used the same analysis procedure to compare 1982 and 1996 population estimates. The 1996 population estimate was 55,721 ± 3,846 SE (48,345–63,495 95% CI), which is 57% higher than our estimate of 35,846 ± 2,211 SE (31,668–40,337 95% CI) for 1982. Vegetation densi- ty, measured by canopy cover and lateral visibility at each station, has also increased since 1982. Our data suggest that the Tinian Monarch population has increased possibly due to increased habitat availability, but remains at risk both from an accidental introduction of brown tree snakes (Boiga irregularis) to the island and stochastic processes. Introduction The Tinian Monarch ( Monarcha takatsukasae), locally known as Chuchurican Tinian, is a monarch flycatcher found only on the island of Tinian, Commonwealth of the Northern Mariana Islands (CNMI), in the western Pacific islands of Micronesia. The terrestrial avifauna of Micronesia has a high propor- 1 Present address: Piedmont National Wildlife Refuge, 718 Juliette Rd., Round Oak, GA 31038. 2 Present address: 522 S. 10th Street, Bozeman, MT 59715. 3 Present address: U.S. Fish and Wildlife Service, 1849 C. St., N.W. (MS-3012MB), Washington, D.C. 20240.