Low Dietary Importance of Polychaetes in Opportunistic Feeding Sanderlings Calidris alba on Belgian Beaches

[摘要] WestudiedabundanceandfeedingbehaviourofwinteringSanderlingCalidrisalbaatfivebeachesalongtheBelgiancoast,andfocusedontheroleofpolychaetewormsintheirdiet.Onaverage10.0Sanderlingswerepresentperkmstretchedbeach,ofwhich87.8%wereinvolvedinforagingactivities.HighestnumbersofSanderlingoccurredonthebeachfrom2hoursbeforeto4hoursafterlowtide.Detailedobservationsofindividualbirdsrevealedameanpeckingrateof18.7peckspermin.Birdsexhibitedseveralfeedingmodes,andwedistinguishedsuperficialpecking(mainlyfeedingonwreck)andprobingforpolychaetes.Feedingonwreckwasobservedfrequentlyandthroughoutthetidalcycle.Incontrast,probingforpolychaeteswaslimitedintime,andoccurredprimarilywhenthetidereachedtheupperintertidalzone,wherepeakdensitiesofScolelepissquamatawerefound.Basedonourobservations,weconservativelyestimatedthatduringeachtidalcyclethisbenthicspeciesmayprovideonly2.0–9.0%ofaSanderling'sdailyenergydemand.NumbersofSanderlingsappearedtobelowestwhencaptureratesonpolychaeteswerehighest.WethereforesuggestthatpolychaetesareofminorimportanceforSanderlingsforagingalongBelgianbeaches.

[学科分类] 动物科学

[关键词] Sandy Beaches