Timing of Breeding and Reproductive Output in Two Black-Tailed Godwit Limosa limosa Populations in The Netherlands

[摘要] TogetabetterunderstandingofthecurrentpopulationdeclineofBlack-tailedGodwitsinTheNetherlands,wedeterminedreproductiveparametersintwoDutchbreedingpopulationsovertheperiod2002–2005andinvestigatedtherelationshipbetweenreproductiveoutputandtimingofbreeding.Annualmedianlayingdatesrangedfrom14to25April,andmedianhatchingdatesfrom11to28May.Sitesdifferedinlayingdatesbutnotinhatchingdates.Dailysurvivalrateofnestswaspositivelycorrelatedtonestageandwasaffectedbyyearandbytheinteractionofyearandsite,butnotbylayingdate.Thenumberofeggshatchingpersuccessfulnestalsodidnotdependonlayingdate.Maximumchicksurvival(maximumestimateofthenumberofchicksfledgeddividedbythenumberofchickshatchedfromthenest)andtheprobabilityofraisingatleastonechicktofledgingdeclinedsignificantlywithhatchingdate,resultinginadeclineofreproductiveoutputwithlayingdate.Minimumchicksurvivalcorrelatednegativelywithcumulativeminimumtemperatureduringthefirstweekafterhatching.Durationofrainfallduringthechick-raisingperioddidnotaffectchicksurvival.Ourestimatesofreproductiveoutputwerelowerthanfoundinpreviousstudies,andinmostyearsreproductiveoutputwastoolowtocompensateforadultandjuvenilemortality.Fivepossibleproximatecausesfortheseasonaldeclineinchicksurvivalarediscussed:parentalquality,weatherconditions,foodavailability,predationpressureandmowingofthegrasslandhabitat.

[学科分类] 动物科学

[关键词] Meadow Birds