Participant retention in a continental-scale citizen science project increases with the diversity of species detected

Sustaining the efforts of volunteers is a challenge facing citizen science programs. Research on volunteer management shows that a diversity of factors may be correlated with sustained volunteerism. In the present article, we explore retention of participants in a large-scale citizen science project. We focus on Project FeederWatch, a bird-monitoring program. Using data from 17,991 participants, we found that the probability of retention increased with the diversity of species (species richness) reported by a participant, but retention was unrelated to the overall abundance of birds reported. Participants who successfully submitted an observation were more likely to remain in the project the following year (82.0% interannual retention) than people who registered but never submitted an observation (39.7%). Two measures of effort were positively correlated with retention. This work provides a case study for examining how demographic information and scientific data collected by participants can be mined to understand volunteer retention in environmental monitoring projects.