The Avifauna of Kosrae, Micronesia: History, Status, and Taxonomy1 Floyd E. Hayes , 2,5 H. Douglas Pratt , 3 and Carlos J. Cianchini 4 Abstract: Kosrae, the east ern most high island of Micronesia, is a 110 km 2 vol- ca nic island ris ing up to 630 m above sea level. It is seldom visited by birders and or ni thol o gists be cause it is small, iso lated, and lacks any previ ously rec og nized ex tant en demic bird species. We re view the his tory of re search on the island’ s avi fauna and sum ma rize the sta tus of each spe cies, in clud ing doc u men ta tion for six new spe cies: Northern Pintail (Anas acuta ), Gray Plover (Pluvialis squatarola ), Common Snipe (Gallinago gallinago ), Bristle - thighed Curlew (Numenius tahitien- sis ), Red - necked Stint ( Calidris rufi collis ), and Whiskered Tern ( Chlidonias hy- brida ). We dis cuss pre vi ously undescribed vo cal i za tions of en demic taxa and pro vide online ref er ence to re cord ings. We also pres ent supporting ev i dence for the rec og ni tion of two taxa as full bi o log i cal spe cies: Kosrae Fruit Dove (Ptili- nopus hernsheimi; for merly part of the P. porphyraceus com plex) and Kosrae White - eye (Zosterops cinereus, as a split from Gray- brown White- eye, Z. ponapensis ). The avi fauna of Kosrae includes 53 nat u rally oc cur ring spe cies of birds of which 13 breed ing res i dents are extant (2 en demic species, 4 en demic subspe cies) and 2 are ex tinct (both en demic species), 21 are bo real mi grants from breed ing pop- u la tions in the tem per ate Northern Hemisphere (in clud ing 11 ex clu sively Pa le- arc tic migrants and 3 exclu sively Ne arc tic mi grants), 5 are aus tral mi grants from breed ing pop u la tions in the tem per ate Southern Hemisphere, and 12 are vis i- tors from breed ing pop u la tions on tropi cal is lands else where in the Pacifi c. Two ad di tional spe cies have been intro duced; one has a self- sus tain ing fe ral pop u la- tion and the other is extir pat ed. Because of the island ’ s low hu man pop u la tion and rel a tively pris tine en vi ron ment, res i dent breed ing birds are thriv ing with no se ri ous threats to their sur vival at present, ex cept for overhunt ing of the Mi- cro ne sian Imperial Pigeon ( Ducula oceanica oceanica ). K osrae, the eastern most high island of the reefs and a few small sat el lite is lands ( Figure Car o line is lands of Micronesia (5 ° 19 ′ N, 162 ° 1 ). The moun tain ous in te rior is steep, rugged, 59 ′ E) and one of four states that com pose the and un in hab it ed, ris ing up to 630 m above sea Federated States of Micronesia, is a 110 km2 level at Mount Finkol. Precipitation is high, vol ca nic island surrounded by fring ing coral av er ag ing 4,842 mm / yr (Western Regional Climate Center 2004). The vege ta tion is dom- i nated by trop i cal rainforest in the moun tains 1 Manuscript accepted 4 Sep tem ber 2015. 2 Department of Biology, Pacifi c Union College , 1 and mangroves along the coast (e.g., Maxwell Angwin Avenue, Angwin, California 94508. 1982, Cole et al. 1999). Because of its histor i- 3 North Carolina Museum of Natural Sciences, 11 cally low hu man pop u la tion (6,616 hu mans in West Jones Street, Raleigh, North Carolina 27601 2010 with a den sity of 54.7 / km2 ; Gorenfl o (e - mail: dpratt14 @ nc.rr.com; website: www.hdoug laspratt 1993, Offi ce of SBOC 2013), which is concen- .com ). 4 P.O. Box 495, Kosrae, Federated States of Microne- trated along the coast, the en vi ron ment of sia 96944 (e- mail: cjcianchini@ ya hoo.com). Kosrae re mains rel a tively pris tine. Segal (1989) 5 Corresponding au thor (e - mail: fhayes @ puc.edu). pro vided an ex cel lent trea tise on the island ’ s his to ry, cul ture, gov ern ment, and econ o my, but some of his in for ma tion on its nat u ral his- Pacifi c Science (2016), vol. 70, no. 1:91–127 doi:10.2984/70.1.8 tory is in ac cu rate. © 2016 by University of Hawai‘i Press Kosrae is seldom visited by birders and or- All rights re served ni thol o gists be cause it is small, iso lat ed, and 91 92 PACIFIC SCIENCE · Jan u ary 2016 F igure 1. Map of Kosrae, Federated States of Micronesia. un til now lacked any pre vi ously rec og nized known of the avi fauna of Kosrae, in clud ing ex tant en demic bird species. The avail able in- doc u men ta tion for six new species for the is- for ma tion on the avi fauna of Kosrae is widely land. We also dis cuss previ ously undescribed scattered in the techni cal lit er a ture and has vo cali za tions of en demic species and sub spe- been dom i nated by re ports of new or un usual cies, and we present supporting ev i dence for spe cies, which of ten neglected to re port de- the rec og ni tion of three taxa as full bi o log i- tails of pre viously recorded species. The only cal spe cies. sum ma ries of the avi fauna since Baker’ s (1951) com pre hen sive re view of the birds of Micro- meth ods nesia in clude fi ve checklists with a few sym- bols denoting the sta tus or a lit er a ture source We reviewed the per ti nent lit er a ture on the for the oc cur rence of each spe cies on Kosrae birds of Kosrae, gleaning data on col lec tors (Owen 1977, Pyle and Engbring 1985, Pratt and ob serv ers, the ranges of dates in which et al. 1987, Engbring et al. 1990, Wiles 2005). they vis it ed, their ob ser va tions of birds, re- As a con sequence, it is cumber some for re- ports of spec i mens collect ed, the muse ums in searchers to ex tract infor ma tion on the status which spec i mens were de pos it ed, and the of the island ’ s birds. The pur pose of this pa- Kosraean names of birds. We also reviewed per is to provide a detailed sum mary of or ni- the avail able online cat a logs of spec i mens of tho log ical his tory and overview of what is var i ous mu se ums, includ ing those in the Avifauna of Kosrae · Hayes et al. 93 ORNIS 2 da ta base (ornis2.ornisnet.org); how- among in su lar pop u la tions pro posed by Pratt ev er, not all mu se ums po ten tially hosting (2010), with a fo cus on po ten tial iso lat ing spec i mens from Kosrae have posted their cat- mech a nisms, geo graphic dis tance (i.e., degree a logs online. We also searched for ar chived of iso la tion), qua si - clinal vari a tion, and com- re cordings of bird vo cal i za tions from Kosrae par i sons with closely re lated spe cies. Popula- in the Macaulay Library of the Cornell Uni- tions that have ob vi ous po ten tial isolat ing versity Laboratory of Ornithology (macaulay- mech a nisms in two or more quali ta tively dif- library.org) and the online source xeno - canto fer ent categories are con sid ered spe cies unless ( www.xeno-canto.org ), spon sored by the proven oth er wise. This view con sid ers ge netic Xeno - canto Foundation with sup port from data in for ma tive but not es sen tial to tax o- the Naturalis Biodiversity Center. Our online nomic de ci sions and follows Gill ’ s (2014) re- searches yielded pre vi ously unpub lished data cent pro posal to shift the bur den of proof in for both skin and acous tic spec i mens. spe cies - level tax on omy of birds. All tax o nomic We com piled a list of bird spe cies reported com ments herein were contrib uted by H.D.P. from Kosrae. We consid ered a species to be Acronyms for muse ums and sound ar chives documented if its oc cur rence was based on are as fol low: AMNH = Amer i can Museum ver i fi able phys i cal ev i dence such as a speci- of Natural History, New York, New York; men, pho to graph, or sound record ing. Un- BPBM = Bernice Pauahi Bishop Museum, Ho- documented sight re cords were eval u ated nolulu, Hawai‘ i; DMNH = Del a ware Mu- based on the in for ma tion avail able to us. Each seum of Natural History, Wilmington, spe cies was placed into one of three catego- Del a ware; FMNH = Field Museum of Na- ries: (1) natu rally oc cur ring species, (2) in tro- tural History, Chicago, Il li nois; ML = Ma- duced species, and (3) hy po thet i cal species caulay Library, Cornell Lab of Ornithology, whose presence on Kosrae has been in ad e- Ithaca, New York; MCZ = Museum of Com- quately documented.