Environmentally-Mediated Flexible Foraging Strategies in Brown Boobies in the Gulf of California

[摘要] TheBrownBoobySulaleucogasterisaseabirdwithapantropicaldistributionacrossawidevarietyofoceanicenvironments.SexualsizedimorphisminBrownBoobieshasbeenproposedasanexplanationforintersexualdifferencesinforaging,butresultshavebeeninconsistent.Weinvestigatedwhetherthereiscontext-dependentforagingbehaviourdrivenbylocalenvironmentalconditions.Inthisstudy,weevaluated(1)inter-sexdifferencesinforagingbehaviour(bycapillarytubes,temperatureanddepthrecorders,anddiet)attwocoloniesintheGulfofCalifornia:IslaSanJorge(ISJ)andFarallóndeSanIgnacio(FSI)and,(2)intercolonialandinterannualdifferencesinforagingbehaviour,and(atISJ)theirrelationshipwithlocal-scaleenvironmentalvariation,using5-daycompositeimagesofseasurfacetemperature(SST)andprimaryproductivity(PP)asproxies.Inter-sexdifferenceswerefewandinconsistentbetweenyears,andsmallerthanoveralldifferencesbetweenyearsandlocalities.AtISJ,BrownBoobiesincludedmorepreyspeciesintheirdiet(27vs.19spp.)anddoveshallower(2.3vs.3.14m)thanatFSI.AtISJ,BrownBoobiesexhibitedadjustmentsindivingdepthandpreysizeasafunctionofenvironmentalvariation:shallowerplungedivesandsmallerpreyitemswererelatedwithlowerSSTandhigherPPvalues,whereasdeeperdivesandlargerpreyitemswererelatedwithhigherSSTandlowerPPvalues.OurresultsconfirmedthattheBrownBoobyishighlyplasticinitsforagingecology,whichexplainsitsabilitytoliveinplaceswithlarge-scaleenvironmentalvariation(intercolonyandinterannual),suchastropicalareasworldwide.

[学科分类] 动物科学

[关键词] Sula Leucogaster