bird measurement

Bird measurement or bird biometrics are approaches to quantify the size of birds in scientific studies. The measurements of the lengths of specific parts and the weights of birds varies between species, populations within species, between the sexes and depending on age and condition. In order for measurements to be useful, they need to be well defined so that measurements taken are consistent and comparable with those taken by others or at other points of time. Measurements can be useful to study growth, variation between geographically separated forms, identify differences between the sexes, age or otherwise characterize individuals birds. While certain measurements are regularly taken in the field to study living birds some others are applicable only to specimens in the museum or measurable only in a laboratory. The conventions used for measurement can vary widely between authors and works, making comparisons of sizes a matter that needs considerable care.