Sexual Dimorphism and use of Morphological Measurements to Sex Adults, Immatures and Chicks of Rockhopper Penguins

Ardea

Maud Poisbleau³  Laurent Demongin³  Petra Quillfeldt¹  Hendrika J. van Noordwijk¹  Ian J. Strange² 

[1] 1 Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Schlossallee 2, 78315 Radolfzell, Germany;3 New Island Conservation Trust, New Island, FIQQ IZZ, Falkland Islands;1 Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Schlossallee 2, 78315 Radolfzell, Germany2 University of Antwerp, Campus Drie Eiken, Dept Biology - Ethology, Universiteitsplein 1, 2610 Antwerp (Wilrijk), Belgium

关键词: Age Class;   

DOI  :  

学科分类：动物科学

来源: Nederlandse Ornithologische Unie/Netherlands Ornithological Union

【 摘 要 】

Followingrecentphylogeneticwork,RockhopperPenguinsweresuggestedtoconsistoftwoorthreespecies.FortheSouthernRockhopperPenguinEudyptesc.chrysocome,sexualdimorphismhasnotbeenstudiedindetail,andonlyafewpreviousstudiesonpenguinshaveinvestigatedsexualdimorphisminimmaturesandchicks.Usingdataintheliterature,weexaminedwhetherthesexualdimorphismofadultsvariesamongthethreetaxaofRockhopperPenguinsandthenweinvestigatedthemostreliablemeasurementstosexadultRockhopperPenguins.Weobservedthatbilllengthisthemostusefulmeasurementtoseparatemalesfromfemales.Toallowforsexdiscriminationinthefield,wealsoexaminedalargedatasetofSouthernRockhopperPenguinsfromNewIsland,FalklandIslands,includingadultssexedviaobservationofbehaviour,andimmaturesandchickssexedgenetically.Wefoundthatmaleadultsandimmatureswerelargerthanfemalesinbilllengthandbilldepthand,toalesserdegree,inflipperlengths.Wethusderiveddiscriminantfunctionsfrombilllengthandbilldepthandcorrectlysexed96.2%ofadultsand91.8%ofimmatures.Innewlyhatchedchicks,maleshadalongerbillthanfemales,butsexingwasonlysuccessfulfor63.5%ofhatchlings.Justbeforethecrècheage(18and19days)andafterthepre-fledgingmoult(55daysandolder),allmorphologicalmeasurementsofchicksweresignificantlydifferentbetweensexes,andsexdeterminationwassuccessfulfor68.2%and84.3%ofchicksintheseagegroups,respectively.Consistentlyamongagegroups,billlengthwasthemostdimorphiccharacterinthispopulation.

【 授权许可】

Unknown