Current Projects

Waterfowl wintering at the Upper Ouachita NWR in NW Louisiana

Metal Contaminants in Wintering Waterfowl

Studies of captive waterfowl have shown that metal contamination can adversely affect their body condition.  Poor winter body condition may negatively affect survival and reproduction.  We are examining metal contaminants in tissues of ducks donated by hunters hunting in Wildlife Management Areas in Louisiana. Birds are known to sequester metals in their feathers, Since the feathers of ducks wintering in Louisiana are grown on their summer breeding grounds, we can disentangle contaminants that may have accumulated in tissues at different life history stages. Species that feed at different trophic levels may be expected to accumulate metals at different rates.

Immunological Memory in Nazca Boobies

Short-lived taxa typically have large broods and low adult survival making the fitness value of current offspring greater than the potential fitness value of future offspring. Decreased immune capability in short-lived parents can be viewed as an allocation of resources to additional offspring, or into higher quality offspring, at the expense of parental self-maintenance. In contrast, pelagic seabirds have fewer extrinsic causes of adult mortality, so the relative importance of the adult fitness component is higher than in short-lived species.  Under this
contrast, pelagic seabirds should make relatively higher allocations of resources to adult self-maintenance functions compared to those of short-lived species.

With collaborators from Wake Forest University, we are examining immunological memory in a population of Nazca boobies, a long-lived seabird, living in the Galápagos Islands, Ecuador,

Above is the expected outcome of initial and second injection with antigen or water (arrows with dashed lines). The experimental group (solid line) is injected twice, while a primary response control group (long dashed line) is only injected once. Other control groups are only injected with water. Only the experimental group should exhibit both primary and secondary immune responses.

Henslow's Sparrow

Winter Ecology of Grassland Sparrows

With colleagues from University of Western Ontario, we are investigating habitat use and survival of  Henslow's Sparrows wintering in Louisiana. Many of the sparrows that winter in Louisiana breed in declining and increasingly fragmented prairie habitats. We are using stable isotopes to link our birds with their breeding sites. Linking breeding sites with winter survival may identify areas important for the conservation of this threatened species.

Avian Survival and Production in a Restored Short Leaf Pine Community

Upland short leaf pine communities were essentially eradicated in Louisiana, but, with the cooperation of The Nature Conservancy and landowner Dr. Johnny Armstrong, a 400-acre area is being restored at Wafer Creek Ranch in Ruston, Louisiana. It will be important to monitor the presence and performance of species in the area as the restoration progresses.

Old growth short leaf pine at Wafer Creek Ranch

A controlled burn at Wafer Creek Ranch

Feather grass growing at Wafer Creek Ranch after a controlled burn

Nazca Booby parent and offspring

Reproductive Senescence

Birds are often long-lived, despite higher metabolic rates and total lifetime energy expenditures, body temperatures, and blood glucose levels, compared to mammals of equivalent mass. Under the disposable soma theory of aging, elevation of these parameters in birds should accelerate damage to cells, proteins, and DNA from the accumulation of deleterious by-products of metabolism. Study of aging processes in
long-lived wild seabirds offers an important perspective on mechanisms involved in aging across taxa, including humans. With collaborators from Wake Forest University and University of Houston, we are investigating reproductive and actuarial senescence in Nazca boobies using serum samples to track biomarkers of health, stress, and immune function across lifespan. .

Monitoring Nocturnal Avian Migrants

Most nocturnally migrating bird species are therefore known to vocalize.  Acoustic monitoring of nocturnal migrants is a relatively inexpensive method of providing presence and movement information of birds that are difficult to visually detect and study. These data are critical for establishment of conservation corridors, placement of wind turbines or communication towers, and detection of altered migration behavior with changing climate.

In collaboration with Old Bird, Inc., Ithaca, NY, we have established an acoustic monitoring station on the Louisiana Tech campus that records the calls of migrants each night.

Microphone on the roof of Carson-Taylor Hall on the campus of Louisiana Tech University

Nesting Loggerhead Shrike

Historic Avian Nesting Distributions in Louisiana

Ornithology classes at Louisiana Tech, from the 1960s through the 1980s, collected information about nesting birds in Louisiana. We are digitizing this information to determine the historic nesting ranges of birds in our area. This information can be used to see how the reproductive success and distribution of species has changed over time.