Charles Clarkson Harbor Herons Meeting Staten Island NY 13 January 2011 Photo Gerald Frost Objectives Use ptilochronology feather growth to predict measures of parental quality diet and mercury burden in mixed species waterbird colonies at two locations along the east coast and demonst ID: 259726
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Slide1
Habitat, Nutrition, and Mercury in Waterbirds: Ptilochronology as a Novel Bioindicator Tool
Charles Clarkson
Harbor Herons MeetingStaten Island, NY13 January, 2011
Photo: Gerald FrostSlide2
Objectives
Use ptilochronology (feather growth) to predict measures of parental quality, diet, and mercury burden in mixed species waterbird colonies at two locations along the east coast and demonstrate its worth as a universal bioindicator tool in avian studies.Slide3
Ptilochronology
Technique of measuring feather growthGrowth-bars laid down in 24 hr increments
Correspond directly with nutritional condition of the individualNever used as a tool for bioindicationSlide4
Predictions
1)Intraspecific variation in feather growth-bar width within a colony site will be indicative of variation in parental investment, as “higher quality” adults will provision nestlings more efficiently.
2)Intraspecific variation in feather growth-bar width between multiple colony sites will be indicative of differing habitat qualities (quality/quantity of diet, contaminant load). Slide5
Hoffman Island
Canarsie Pol
Chimney Pole
Chincoteague Causeway
Googlemaps.com
Methods: Study SitesSlide6
Methods: Study Species
Two species belonging to the same waterbird guild yet representing two endpoints of foraging habit.
Glossy Ibis (Plegadis falcinellus)Tactile foragerInvertebrates and mollusksForaging habit delimits spatial exploitationDouble-crested Cormorant (Phalacrocorax auritus)Habitat generalistFree-swimmingPiscivorous
Photos: Gerald FrostSlide7
Growth-bar AnalysisSlide8
Fault BarsSlide9
Future Directions
Model growth-bar width as a predictor variable:
Akaike’s Information CriterionAICc = N*ln(SS/N)+2K+(2K(K+1))/(N-K-1)
Captive food supplementation study
National Zoo, Washington D.C
White-faced Ibis (
Plegadis
chihi
)
Scarlet Ibis (
Eudocimus
ruber
)
Colony-wide biomass consumption
How much biomass is consumed during the breeding season?
All nesting species (~8
spp
)Slide10
Acknowledgements
Mike ErwinSusan Elbin
Mark KopenyJohn PorterCarleton RayMatt ReidenbachUVA; VCR LTER; NYC Audubon; American Littoral Society; Virginia Society of Ornithology; National Park Service; NYC Parks Friends and Family