Selective Forces Responsible for Transition to Nesting on Electricity Poles in the White Stork Ciconia ciconia

[摘要] TheprocessoftransitionfromnestingontreestoelectricitypoleshasbeenobservedoverthelastdecadesinmanyEuropeanpopulationsoftheWhiteStorkCiconiaciconia,butthedirectmechanismsbehindthisprocesshavenotbeenexplicitlyidentified.Theaimofthisstudywastoidentifyselectiveforcesresponsiblefortransitiontonestingonelectricitypolesusinglong-termdata(1994–2011)collectedforthecentralPolishpopulationofc.190breedingpairs.Wehypothesizedthattransitiontonestingonelectricitypolescouldbeexplainedbytwonon-exclusivemechanisms.Firstly,theprocesscouldbedrivenbyinsufficientavailabilityoftraditionalnestingsitesinthevicinityoffavourableforaginggrounds.Secondly,nestingonelectricitypolescouldbedirectlyassociatedwithfitnessbenefitsresultingfromdifferentneststructureandmicroclimate.Wefoundthattheprocessoftransitionhadstartedandproceededatthehighestrateinthegood-andmedium-qualityareasofrivervalleys,wheremostintensecompetitionfornestingterritoriesandhigheststorkdensitieswererecorded.Bycontrast,wefoundlittlesupportfordirectfitnessbenefitsassociatedwithnestingonelectricitypoles.Infact,reproductivesuccess(numberoffledglingsperpair)ofstorksnestingonpoleswaslowerincomparisontothosenestingontrees,butthisrelationshipprevailedonlyintheareasofpoorquality(dryagriculturallandscape).TheresultsstronglysuggestthattheprocessoftransitiontonestingonelectricitypolesintheWhiteStorkisnotfacilitatedbydirectreproductivebenefits,butcouldbedrivenbydecreasingavailabilityofnaturalnestingsitesintheattractivebreedingareas.

[学科分类] 动物科学

[关键词] Reproductive Success