habitat, nutrition, and mercury in waterbirds: ptilochronology as a novel bioindicator tool
DESCRIPTION
Habitat, Nutrition, and Mercury in Waterbirds: Ptilochronology as a Novel Bioindicator Tool. Charles Clarkson Harbor Herons Meeting Staten Island, NY 13 January, 2011. Photo: Gerald Frost. Objectives. - PowerPoint PPT PresentationTRANSCRIPT
HABITAT, NUTRITION, AND MERCURY IN
WATERBIRDS: PTILOCHRONOLOGY AS A
NOVEL BIOINDICATOR TOOL
Charles ClarksonHarbor Herons Meeting
Staten Island, NY13 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 demonstrate its worth as a universal bioindicator tool in avian studies.
Ptilochronology• Technique of measuring
feather growth– Growth-bars laid down in 24 hr
increments– Correspond directly with
nutritional condition of the individual
– Never used as a tool for bioindication
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).
Hoffman Island
Canarsie Pol
Chimney Pole
Chincoteague Causeway
Googlemaps.com
METHODS: STUDY SITES
METHODS: STUDY SPECIES• Two species belonging to the same
waterbird guild yet representing two endpoints of foraging habit. – Glossy Ibis (Plegadis falcinellus)
• Tactile forager• Invertebrates and mollusks• Foraging habit delimits spatial exploitation
– Double-crested Cormorant (Phalacrocorax auritus)• Habitat generalist• Free-swimming• Piscivorous
Photos: Gerald Frost
GROWTH-BAR ANALYSIS
FAULT BARS
Future Directions• Model growth-bar width as a
predictor variable: Akaike’s Information Criterion• AICc = 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)
ACKNOWLEDGEMENTS• Mike Erwin• Susan Elbin• Mark Kopeny• John Porter• Carleton Ray• Matt Reidenbach• UVA; VCR LTER; NYC Audubon; American Littoral Society;
Virginia Society of Ornithology; National Park Service; NYC Parks
• Friends and Family