Air Pollution and Hummingbirds
A multidisciplinary team of EPA-RTP ORD pulmonary toxicologists, engineers, ecologists, and statisticians have designed a study of how ground-level ozone and other air pollutants may influence feeding activity of the ruby-throated hummingbird (Archilochus colubris). Because hummingbirds breathe many times more air per body weight than mice (which decrease their spontaneous wheel running activity with ozone exposure), they may also experience adverse effects from ozone. Building on a preliminary study design that Dr. Gary Hatch (NHEERL) developed, the study can provide valuable information on the effects of air pollutants on wildlife that ecologist Dr. Timothy Lewis (NCEA) may incorporate into future Air Quality Criteria Documents.
NHEERL engineers Allen Ledbetter and George Hudson devised a system for monitoring hummingbird feeder activity using infrared sensors to detect the birds' body heat. Data on the number of hummingbird visits and each bird's length of time at the feeder was transmitted to a remote data logger for analysis. Ozone monitoring and meteorological data serve as independent variables. The first two years of the study allow for adjustments to the feeder platform, electronics, and software.
Statisticians Drs. David Svendsgaard (NCEA) and Najwa Haykal Coates (NHEERL) will employ methods similar to those used in epidemiologic time-series studies of air pollutant effects on humans. However, they expect less exposure measurement error because hummingbirds are territorial and tend to stay in one area, unlike humans who are more mobile during ozone exposure periods.