Management of European Starlings in an American Kestrel Nest Box Program

Abstract

ABSTRACT Artificial nest boxes have played an important role in American Kestrel (Falco sparverius) conservation worldwide, facilitating nesting and research efforts. However, these conservation efforts frequently unintentionally facilitate other cavity-nesting species including the European Starling (Sturnus vulgaris), a widespread invasive species in North America. Understanding how to deter European Starlings from occupying nest boxes is an essential responsibility of project design when deploying nest boxes. We examined the efficacy of five different abatement methods to mitigate the use of our nest boxes by European Starlings: nest removal, nest and egg removal, egg shaking, egg cracking, and egg oiling. We found spraying European Starling eggs with 100% food-grade corn oil and cracking eggs to be the most effective abatement methods. We recommend future American Kestrel nest box programs in this region use egg oiling or egg cracking on European Starling eggs.