As a group, birdwatchers and other citizen scientists conduct observations across geographic and temporal scales that are generally much larger than those available to formal research science, which is constrained by limited resources and personnel. By virtue of their large population, such citizen scientists carry a high diversity of experiences. Furthermore, many of them demonstrate real and substantial expertise in their chosen areas of interest. Important insights might thus be gained by partnering with them as information sources. Research scientists and managers, however, rarely utilize citizen scientist observations because they are frequently difficult to obtain, may be qualitative rather than quantitative, and are hard to verify. While these limitations are valid, we argue that citizen scientist observations often have heuristic value, and should then be utilized to guide more formal and quantifiable research and thereby to streamline research resource distribution. To explore the potential of such interchange, we surveyed 172 birdwatchers, asking them to describe their observations of bird relationships with nonnative plants.   

Results/Conclusions

Survey responses contained a wealth of anecdotal information. In all, 1215 distinct bird-plant interactions were reported, comprising 867 pairwise bird-plant relationships. Interactions included a total of 120 plant species and 172 bird species. Almost half of all reported interactions (598) involved birds feeding on fruits or seeds of nonnative plants, identifying these pairs as potential dispersal mutualists. Meanwhile, 617 “habitat interactions” described use of nonnative plants by birds in non-dispersal capacities. Prominent among these were nonnative plants serving as cover and perch sites (35% of all habitat interactions) and bird use of nonnative plants for nesting (25% of all habitat interactions). Survey results may therefore be of interest to both invasion ecology and avian conservation. We have used the information obtained in this survey to initiate and shape our ongoing analysis of the role of bird dispersal in plant invasions in California.