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: December 2012

Status:
On-going

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, 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. 48^th Annual Meeting, Texas Chapter of The Wildlife Society, Fort Worth, Texas.