This tool allows the exploration of the date of occurrence of 34,000+ records in the Maine Butterfly Survey database. Choose a Focal Species of interest from the drop-down menu to the left. You can restrict the search to particular intervals with the Start and End Year drop-down menus. You can set the width of each bin in days from one to ten.
If desired, the histogram for a second and third species can be overlain on the histogram for the Focal Species. Choose species using the Optional second species and Optional third species drop-down menus. The species are coded by transparent colors. A legend to the right gives the color of each species. Darker portions of the histogram indicate the abundance of the less common species. It's easy to get the hang of the technique for two species. Toggle a second species off and on using the None option in the drop-down menu to learn how to interpret the graph. Deciphering three species can be more challenging.
Created and maintained by Herb Wilson (email@example.com)