Using Digital Photographs to Evaluate the Effectiveness of Plover Egg Crypsis

Abstract: The focus of digital photography has moved from documentation to quantitative analysis. To illustrate the potential application of this diagnostic tool to quantify color and shape, we photographed both artificial and natural semipalmated plover (Charadrius semipalmatus) nests to determine what benefits, if any, were derived from egg crypsis (i.e., eggshell color and egg marking shape). This simple and cost-effective method provides precise and repeatable quantification of color and shape that discriminated subtle differences in egg crypsis of artificial and natural nests that were not visible to us. The advantages of digital photography and image-editing software outweigh any shortcomings, as long as standard protocols are followed for capturing and analyzing images. Used with due care, digital photography is useful in studies that need to quickly assign biological traits, such as age and sex, to individuals, and to document temporal change that may occur as a response to management or disturbance.