Date of this Version
We conducted surveys of federal officials nationwide and of local officials in California to determine historical and temporal aspects, location, size, and control of American crow (Corvus brachyrhynchos) urban roosts. The national survey consisted of a 2-page questionnaire sent via email to United States Department of Agriculture Wildlife Services state directors representing the lower 48 states. The California survey consisted of a 3-page questionnaire mailed by the League of California Cities to 473 towns and cities and an email inquiry sent to Agriculture Commissioners in 29 counties. In the national survey respondents in 27 of 39 states identified 86 urban and 15 rural roosts. Most urban roosts (n = 69) were used in the fall, winter, or spring and had been occupied for <30 yr (n = 59). Most respondents (n = 26) didn't know if a shift from rural to urban roosts had occurred, but 12 said it began in the 1970s and continued into the 1990s, with most roosts now in urban locations in 11 states. Based mainly on personal observations and the number of complaints received, respondents indicated crow populations had increased in 27 states. In the California survey 17 Agriculture Commissioners and 206 cities responded, identifying 57 cities with crow problems including 24 with night roosts. Cities responded to citizens' complaints most often by giving advice on control methods (n = 20). Most control efforts consisted of individual efforts by residents or businesses; only 3 cities attempted large-scale organized efforts led by local officials. Respondents listed 14 techniques used for crow control. Only poisoning, firearms, pyrotechnic devices, and sticky contact repellents received good ratings. Most respondents indicated roosts had been in their city for <30 yr (n = 14) and about 50% said crow populations had increased. Results suggest crow populations are increasing, a shift to urban roosts has occurred and is still in progress in some regions, and problems with urban crow roosts are likely to increase. New strategies and techniques are needed to disperse roosts on a large scale.