Apparatus for the Study of Incubated Bird Eggs

Abstract

seemed commensurate, either qualitatively or quantitatively, with the effort involved. Because field studies usually demand considerable time, often with only limited findings in prospect, it is important that as much basic information as possible be obtained from each series of observations. This may mean approaching a study with a fresh viewpoint or with more adequate instruments that will permit the gathering of new or more precise data. With this thought in mind, the writer developed an egg volumeter and a portable egg candler. While egg candling no doubt dates back hundreds of years, an adequate device for use in the field does not seem to have been developed. In addition to these instruments, which are described below, a method of photographing incubated eggs by transmitted light was also developed to provide photographs for comparison in estimating more accurately the incubation stage of candled eggs. Photographs have been taken of the day by day development of the eggs of the mallard (Anas platyrhynchos), wood duck (Aix sponsa), bob-white quail (Colinus virginianus) and mourning dove (Zenaidura macroura) which greatly increase the usefulness of an egg candler in studying these species. These photographs will appear elsewhere, but for those who may be interested in obtaining serial photographs of the development of the eggs of other species, the techniques used are described.