The Ongoing Decline of the Breeding Population of Black-Tailed Godwits Limosa l. limosa in The Netherlands is Not Explained by Changes in Adult Survival

摘要

TheBlack-tailedGodwitLimosalimosaisacharacteristicbreedingwaderofwetgrasslandsinTheNetherlandswhichhassufferedastrongpopulationdeclinesincethe1960s.Lowbreedingsuccesshasbeenimplicatedasthemaindriverofthisdeclineandhereweexaminewhetherchangesinadultsurvivalcouldalsohaveplayedarole.Adultgodwitswerecolour-ringedandresightedfrom2002through2005atfourstudysitesinTheNetherlands.ApparentadultsurvivalwasestimatedinprogramMARKusingBurnham'smodelforbothliveresightingsanddeadrecoveries.Inaddition,nestsitefidelitywasestimatedattwoofthesitesbyrecordingthedistancebetweennestlocationsinsuccessiveyears.Apparentadultsurvivalwas0.93(SE0.03)inonestudyareaand0.81(SE0.04)intheotherthreesites.Overallapparentadultsurvivalwas0.83(SE0.03).Thesevaluesaresimilartoestimatesfromthe1970sand1980s.Nestsitefidelitywashigherinthesitewithhighestsurvival(mediandistancebetweennestsinsuccessiveyears:49mvs.252mintheothersite),suggestingthatthedifferenceinapparentsurvivalmayresultfromdifferencesinemigrationrates.Thus,ourresultssuggestthatcurrentadultsurvivalisnotdifferentfromrates30yearsago,andthereforedonotpointtoreducedadultsurvivalasthedriverbehindthecurrentpopulationdeclineofBlack-tailedGodwits.