A PIGEON'S EYE VIEW OF A UNIVERSITY CAMPUS

Abstract

Increasing urbanization over the last century has resulted in a greater abundance of invasive species. Invasive feral pigeons (Columba livia) damage critical urban infrastructure and pose risks to human health. Universities, including Texas Tech University (TTU), located in Lubbock, Texas, have difficulty decreasing adverse effects caused by pigeons. Assessing reliable estimates of population demographics is an important first step to understanding and managing damaging pigeon populations. Our goal was to estimate pigeon abundances at TTU and understand the underlying mechanisms that facilitated pigeon persistence on campus. We surveyed 23 independent locations from March to April 2017 to estimate pigeon abundance across the entire campus. Separately, we also examined pigeon densities on two campus buildings from March to December 2017 to assess and quantify variation in pigeon detection probabilities and abundance both during the diurnal period and among calendar seasons. Our estimates suggested campus abundance was comparable to other urban areas (1,584.4 pigeons/km2, SE = 43.58, 95% CI = ±1,969). Our results indicated hot spots (i.e., high pigeon abundances) existed on campus; for example, we estimated ∼2,819 pigeons (SE = 76, 95% CI = ±138) on a single building on campus during our surveys. Enumeration of pigeon abundance on two campus buildings (mean = 326, SE = 16, 95% CI = ±11) indicated abundance was greatest in the fall and during the morning hours, and peak abundance occurred shortly after 0700 h and declined during the day. Our results suggested pigeons were abundant on campus due to structure and composition of buildings that facilitated nesting and loafing spots that likely maximized efficiency and effectiveness of thermal regulation as well as direct access to water during the study period. In general, pigeons clustered on two buildings on campus and our findings suggested success of population-control measures may be maximized if they are implemented around these buildings.