Biomonitoring, “the use of bio-organisms/materials to obtain (quantitative) information on certain characteristics of the biosphere” (Wolterbeek 2002), is a widely used method to evaluate environmental quality. For example, lichens, mosses, and trees are often used to assess changes in air pollution severity over space and time. In the context of local, regional, and continental-scale air pollution, avian biomonitoring also offers advantages. Birds are mobile, providing a spatially-integrated measure of environmental pollution, and blood, urine, and feathers can be sampled non-destructively. Previous research shows that feathers, specifically, are useful for tracking bioaccumulation of atmospheric pollutants (e.g., Jaspers et al.). Few studies examine external deposition of airborne pollutants to bird feathers despite their potential to record changes in pollutant concentrations over space and time.

Over the past three years, we have conducted two research studies investigating elemental carbon and particulate matter accumulation on bird feathers. We conducted a small experiment with molted chicken feathers in the City of Denton that demonstrated that bird feathers accumulate detectable quantities of elemental carbon and that accumulation rates vary over short distances (Pitre et al. 2021). Our findings suggested that bird feathers  potentially could be used as biomonitors of airborne elemental carbon. We completed a  study that examines whether urban rock pigeons (Columba livia) can in fact be used to this end (Ellis et al. 2023).