Today marks the start of the annual Christmas Bird Count, a bird census sponsored by the National Audubon Society that also happens to be the longest-running citizen scientist survey in the world. Each year the count runs from December 14 to January 5, giving bird lovers across North America a chance to join in, get outside, and spot some birds. The findings recorded by participants are collected and used to gauge the health of various bird populations. This information is then used to focus conservation efforts on particular species and geographical areas.