Late-Hatched Great Tits Parus major: How Do They Contribute to the Next Year Breeding Population?

[摘要] Late-hatchedGreatTitsParusmajorhaveoftenalowerlocalrecruitmentratethanthosehatchedearly.However,estimatesofrecruitmentusuallyneglectdifferentialdisappearanceduetodispersal.Wereportontheproportionsoflate-hatchedbreedersintwoGreatTitbreedingpopulations(nearSt.Petersburg,NWRussia,andontheCourishSpit,EasternBaltic).Usinganovelmethod,late-hatchedbirds(hatchinginJuly)weredistinguishedinthenextbreedingseasonbytheincompletemoultoftheirtailfeathers.Basedonthismethod,wewereabletoestimatethepercentageoflate-hatchedindividualsinallfirst-yearbirds,includingimmigrants.Theproportionoflatehatchedbreederswasconsiderableinsomeyears,andappearedrelatedtotheproportionoflatefledglingsinthepreviousyear.IntheCourishSpitpopulationwefoundnosignificantdifferenceintheglobalrecruitmentrate(accountingforbothlocalbirdsandimmigrants)ofearly-andlate-hatchedGreatTits.IntheSt.Petersburgpopulation,theannualpercentageoflate-fledgedbreederswassignificantlylowerthanthepercentageoflate-hatchedfledglingsinthepreviousyear.However,intheSt.Petersburgpopulationwecannotdefinitelyconcludethattheglobalrecruitmentrateoflatefledglingswaslowerthanthatofearlyfledglingsbecauseofpeculiaritiesofthestudysite.Wealsocansuggestthatitmaybearesultofcompetitionbetweenearlyandlatefledglings,winterresidentsandnewcomersinspring(especiallyinmales),aswellasaresultofdifferentsurvivalofearly-andlate-bornindividualsduringthefirstyear.

[学科分类] 动物科学

[关键词] Extent Of Moult