Wildlife Mortalities in open-topped pipes in Central California

—Nearly 20 billion birds are killed in the United States each year by a number of anthropogenic causes, but a lesser known threat is open-topped pipes. Open-topped pipes are prevalent across the landscape, as they are used for a multitude of purposes including agriculture, mining, and infrastructure. Birds, herptiles, and small mammals can be attracted to the pipes as sites for nesting or shelter but they soon can become trapped by the smooth interior and small diameter. Cavitynesting birds are the most likely animals to enter these pipes, potentially due to competition over a decreasing number of tree cavities in their natural habitat. We inspected pipes in several areas in central California including the South Fork Kern River Valley, Ridgecrest, and Fresno. The main goal of this study was to document the prevalence and predominant taxa comprising the wildlife mortalities in pipes, while also examining the influence of pipe dimensions and adjacent landscape types. We found 13.3% of pipes studied caused mortality: the majority of those mortalities were birds and significantly more deaths were in desert landscapes. The results of this study reveal the need for future research and pipe alteration projects to prevent further mortalities, especially in high priority desert shrubland areas.