Eastern Bluebird Nestling Growth Chart
There are several reasons you might want to know the age of nestlings in a particular nest box. For example, you would want to avoid opening a box with nestlings that are close to fledging age. The North American Bluebird Society has created a handy reference to help nest box monitors judge the age of Eastern Bluebird nestlings. Download the free reference guide here, and keep an eye out for an upcoming guide for Western Bluebirds.
Test your skill: Using the growth chart, see if you can identify the age of the nestlings in the above photo. Check your answer by clicking on the photographer’s name.