Potential Exposure to Environmental Lead in Mottled Ducks (Anas fulvigula) on the Texas Chenier Plains National Wildlife Refuge Complex
Investigators:
Stephen McDowell, M.S. Student, Stephen F. Austin State University
Project Supervisors:
Dr. Warren Conway
Dr. David Haukos
Funding:
U.S. Fish and Wildlife Service
U.S. Geological Survey
Stephen F. Austin State University
Cooperators:
Texas Chenier Plain NWR Complex
Dr. Dan Collins
Patrick Walther
Location:
Anahuac NWR
Completion:
May 2014
Status:
Completed
Objectives:
(1) Determine the availability of lead on the upper Texas Gulf Coast.
(2) Estimate the exposure of lead by mottled ducks.
(3) Evaluate pathways of lead exposure for waterbirds of the upper Texas Gulf Coast.
Progress and Results:
The mottled duck is a non-migratory waterfowl species that depends on the marshes along the Gulf of Mexico. Since the mid-1980s the Texas breeding pair populations have declined, where current population estimates hover around 17,000 individuals. Though use of lead shot was banned nationwide for migratory waterfowl hunting in 1991, recent studies show mottled ducks continue to have elevated wing bone lead concentrations. Such data indicate that mottled ducks continue to be exposed to lead somewhere during the annual cycle. I am estimating blood lead concentrations within local, hatch-year, and adult mottled ducks to isolate when mottled ducks are initially exposed to lead. I am also estimating spent lead shot availability and distribution, as well as soil lead concentrations on the Complex to determine potential pathways by which mottled ducks obtain lead. Such research is important to evaluate long term effects on mottled duck populations and as possible influences on important vital rates, such as survival and fecundity.
Products:
McDowell, P.K., W.C. Conway, D.A. Haukos, J.A. Moon, C.E. Comer, and I.K. Hung. 2015. Blood lead exposure concentrations in mottled ducks (Anas fulvigula) on the upper Texas coast. Journal of the Southeastern Association of Fish and Game Agencies 2:221-228.
Stephen McDowell (M.S. 2014; Advisors: Conway/Haukos). Thesis: Environmental availability and lead exposure to mottled ducks (Anas fulvigula) in the Texas Chenier Plains region. Stephen F. Austin State University.
McDowell, S., W. Conway, C. Comer, D. Haukos, and J. Moon. 2014. Lead exposure concentrations in the blood of mottled ducks (Anas fulvigula) on the Texas Chenier Plains National Wildlife Refuge Complex. Mottled Duck Symposium, Annual Conference of the Southeastern Association of Fish and Wildlife Agencies, Destin, Florida.
McDowell, S., W. Conway, C. Comer, and J. Moon. 2013. Blood lead concentrations in mottled ducks (Anas fulvigula) on the Texas Chenier Plain National Wildlife Refuge Complex. Annual Meeting of The Texas Chapter of The Wildlife Society, Houston, Texas.
McDowell, S., W. Conway, C. Comer, and J. Moon. 2013. Potential exposure of mottled ducks (Anas fulvigula) to lead contaminated soil on the Texas Chenier Plains. Annual Meeting of The Texas Chapter of The Wildlife Society, Houston, Texas.
McDowell, S.K., W. Conway, and D. Haukos. 2012. Potential exposure to environmental lead in mottled ducks (Anas fulvigula) on the Texas Chenier Plains National Wildlife Refuge Complex. 48th Annual Meeting, Texas Chapter of The Wildlife Society, Fort Worth, Texas.
