Energetics of Great Egrets Foraging in Upland Agricultural Fields

[摘要] IexaminedtheforaginganddietenergeticsoftheGreatEgretacrossanuplandlandscapetocomparerelativecostsandbenefitsassociatedwithcommensal,non-commensal,solitaryandgroupforagingstrategies.Acrossstrategies,GreatEgretsusedacombinationofdifferentforagingmodes.Netenergeticgainsandcostsdifferedacrossstrategies.Foragingcostswerelowerforsolitaryegrets,mainlyasaresultofdecreasedforagingtimesandloweraggressionandrelocationfrequencies.Solitaryegretslikelysufferedunmeasuredcostsfromterritoriality,expensivecaptureeffortsandhandlinglargerprey.Groupforagersaccumulatedhighercostsduetohavinglongerforagingtimes,andhigherpursuit,relocationandaggressionfrequencies.Commensalforagershadloweroverallcostsincomparisontosolitaryandgroupforagers.Whenrankedbyenergeticcost-benefitratio,solitaryforagingwasthemostefficientstrategyandgroupforagingstrategiesweretheleastefficient.Theoverallbenefitsfromprofitablefoodsourcesoutweighedtheestimatedcostsofterrestrialforaging.GreatEgretsareecologicallyflexibleandexpandtheirnichebreadthintouplandhabitatswhereampleenergyresourcesareapparentlyavailable.TheGreatEgret'sabilitytocapitalizeondifferentenergysourcesduringdifferentforagingsituationslikelyimprovesforagingefficiencyandenergyintakeovertime.

[学科分类] 动物科学

[关键词] Upland