Risks to Insectivorous Birds in the Calumet Region from Transfer of Contaminants from Sediments to Emergent Aquatic Insects S. Gallo 1, D. Soucek 1, J. Levengood 1, W. Hill 1 and G. Bordson 2 1 Illinois Natural History Survey, Champaign IL; 2 Illinois Sustainable Technology Center, Champaign IL;

Funding: The Illinois Waste Management and Research Center, WMRC (ISTC) Department of Natural Resources and Environmental Sciences, UIUC Center for Ecological Entomology, INHS

Overall Objectives Observational study to quantify contaminant loads in sediments, aquatic insects and tree swallow eggs and nestlings in Calumet, IL. Attempt to understand the movement of contaminants between aquatic and terrestrial ecosystems Use stable isotope analysis to try to determine the source of the contaminants

Contaminants in sediments or water Contaminant Transfer Between Ecosystems: Tachycineta bicolor

Photo: John Marlin

Sites 2 Contaminated Sites –Big Marsh –Indian Ridge 1 “Reference” Site –Powderhorn Lake –No record of contaminants 30 Nest boxes at each site Big Marsh Indian Ridge Powderhorn Lake N

Procedures Collected in 2004 & 2005: Birds: Tree Swallows (Tachycineta bicolor) 2 eggs from each of 10 nests 1 14-day-old nestling from same 10 nests Insects: Emergence traps Benthic samples Bolus material (analyzed for contaminants in 2005 only) Sediment grabs

Analyses 12 priority elements measured: Ag, As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Zn. Approximately 60 different Organics measured: PCBs, PBDEs, DDTs and Other organo-chlorine pesticides

Nesting Ecology

-No differences among sites in # nestlings /nest, nest success, hatch success, fledge success. Nest success ranged from 69 to 83%. -Mass of nestlings at BM and IRM were significantly lower than at PL. Related to greater # eggs/nest (BM > PL in 2004).

Site Vegetation Reference Site: approximately 2x more canopy cover Orthogonal contrasts comparing to Reference: ** <0.01, *<0.05 ***

Diet

Total mass of aquatic or terrestrial arthropods represented in the 2005 boluses. N= 61, 26, 25 for Big Marsh, Indian Ridge and Powderhorn, respectively.

Contaminants

Mercury accumulation ***** Orthogonal contrasts comparing to Reference: *** <0.0001, *<0.05 Growth dilution with no addition mg/kg total Hg dry wt

Synthesizing Ecology and Contaminant Data: Nest Initiation and Egg Hg levels

Contaminant Transfer Pathways: Local and Migratory Local Migratory -Eggs form ~6 days before laying -Hg half-life in other birds is 40 to 84 days -swallows arrive days before laying -at least some Hg in eggs must be from non-local sources

4,4’-DDD in eggs and nestlings

PBDEs in eggs and nestlings

PBDEs in eggs

PBDEs in nestlings

Contaminant sources

Stable Isotopes Measure of light to heavy C and N isotope ratios C13/C12 ratio in organisms changes very little w/ increasing trophic level and can indicate percentage of sources/prey items that are being consumed N15/N14 ratio can indicate trophic level. N15 increases with trophic level because consumers excrete N14 at a faster rate Both can provide insight into long term food resource use rather than short term use (i.e. gut content analyses) Expressed as  15 N and  13 C -- ratio of isotopes in sample relative to ratio in standards (air for N, and Pee Dee Belamite for C).

Stable Isotopes Measure of light to heavy C and N isotope ratios C13/C12 ratio in organisms changes very little w/ increasing trophic level and can indicate percentage of sources/prey items that are being consumed N15/N14 ratio can indicate trophic level. N15 increases with trophic level because consumers excrete N14 at a faster rate Both can provide insight into long term food resource use rather than short term use (i.e. gut content analyses) Expressed as  15 N and  13 C -- ratio of isotopes in sample relative to ratio in standards (air for N, and Pee Dee Belamite for C).

Stable Isotope profiles of bolus insects Big MarshAquatic Terrestrial  15 N  13 C Indian RidgeAquatic Terrestrial  15 N  13 C PowderhornAquatic Terrestrial  15 N  13 C

Sources of contaminants

Conclusions Tree Swallows in Calumet are accumulating a variety of contaminants through their diet Site differences exist Contaminant may be acquired from terrestrial sources more so than aquatic sources Tree swallows prefer to nest at BM and IRM, potentially risking greater exposure to contaminants

Questions?

PCBs in eggs and nestlings