A Review of the Status of the White-Faced Ibis in Winter in California
WESTERN BIRDS Volume 27, Number 4, 1996 A REVIEW OF THE STATUS OF THE WHITE-FACED IBIS IN WINTER IN CALIFORNIA W. DAVID SHUFORD and CATHERINE M. HICKEY, Point ReyesBird Observatory, 4990 ShorelineHighway, Stinson Beach, California 94970 REBECCAJ. SAFRAN, Departmentof Wildlife,Humboldt State University, Arcata, California 95521 GARY W. PAGE,Point Reyes Bird Observatory.4990 ShorelineHighway, Stinson Beach, California 94970 The White-facedIbis (Plegadis chihi) has been classified as a Bird Species of SpecialConcern in California(Remsen 1978, S. Laymonpers. comm.) and a potential candidatefor federal threatenedor endangeredstatus (USFWS 1991, Trapp 1995) becauseof populationdeclines in the western UnitedStates, particularly in the 1960s and 1970s (USFWS 1985, Ryder and Manry 1994). Althoughthe breedingstatus of the ibisin thisregion has been reviewed(Ryder 1967, USFWS 1985, Ryderand Manry 1994), little has been publishedon its abundanceand distributionin winter. Here we summarizedata on the winterdistribution, abundance, and habitatuse of the White-facedIbis in Californiaduring the lasthalf century.We alsoestimate the currentwinter population size and reviewhistorical population trends. METHODS We determined the winter status of the White-faced Ibis from wetland censuses,roost counts, and publishedand unpublishedobservations. As part of Point Reyes Bird Observatory'sPacific Flyway Project, we organized surveysof all shorebirdsand ibisin all key weftandsof California'sCentral Valleyand the Mojave,Colorado, and southernGreat Basindeserts once to twice per winter from November 1992 to February1995. Surveyswere conductedfrom the ground,except in the CentralValley where logistical constraintsdictated a combinationof aerial and groundcounts. The aerial countswere conductedprimarily from a Cessna172 aircraftby Pageand WesternBirds 27:169-196, 1996 169 WHITE-FACED IBIS IN WINTER IN CALIFORNIA Shuford,the groundcounts by a network of skilledvolunteers, agency personnel,and projectstaff.
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