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News releases from the UC Division of Agriculture and Natural Resources
by T V Light
on March 10, 2018 at 1:08 PM
I hope you're not encouraging the use of anticoagulant rodenticides. There are far more humane and environmentally preferable alternatives available, and the University should be mindful of its obligation to the residents of California to behave in a humane and environmentally responsible manner.
Reply by Pamela Kan-Rice
on March 13, 2018 at 7:25 PM
More information about controlling roof rats is in this free publication
by Pamela Kan-Rice
on March 14, 2018 at 1:27 PM
COMMENT FROM UC Cooperative Extension wildlife specialist Roger Baldwin:  
Raptors are a valuable part of our ecosystem, and may provide some pest control benefits as well. However, raptors will not likely be able to reduce rodent populations quickly enough to stay ahead of a population explosion of rodents. Secondly, it is not yet clear how effective raptors can be at managing rodent populations. Just last week, a group of barn owl and rodent experts from around the world came together in Davis for a workshop, and the general consensus among the group members is that we still do not know how effective raptors are at managing rodents. Fortunately, more research is currently underway on this issue, so hopefully we will have a better answer soon.  
UC ANR continues to recommend the use of pesticide as part of an integrated pest management plan. Rodents remain a threat to California agriculture as well as being public health pests, so effective management practices are needed. Many growers are experiencing rapid population growth of roof rats, potentially resulting in substantial losses if the populations are allowed to grow unchecked. Rodenticides are one of the few tools that allow for a rapid depopulation of rodents, and as such, are favored in such circumstances. The bait station methodology mentioned in the article has proven to be a highly effective strategy for managing rodent outbreaks with minimal effects to non-target animals. By placing bait stations in the tree, the applicator is able to eliminate access to those species that cannot climb.  
UC ANR is very aware of the recent research from UC Davis that collected information about the illegal use of rodenticide. However, data derived from this study is based on illegal applications of rodenticides. The legal application of rodenticide in bait stations has been shown to be highly effective for managing rodent outbreaks. Much more study is needed to determine if legal applications have a substantial impact on raptor populations; this is an area receiving much attention, not just globally, but within UC ANR as well. Advisors and Specialists at UC ANR are focusing research and extension efforts on the issue of rodenticide residues in wildlife. Recently one of our Advisors organized a highly successful symposium "Rodenticide Residues in Wildlife" which attracted many of the foremost scientists in this area. Many issues were discussed in a moderated group session after the symposium. Furthermore, our scientists are currently engaged in research addressing pathways for rodenticide exposure, assessing sublethal impacts to nontarget wildlife populations, and methods to reduce exposure from rodenticide application programs. Ultimately, a variety of tools are needed for effective rodent management. We may find that natural predation provides a useful tool for rodent management, but other tools including rodenticides are currently needed to most effectively manage rodent populations.
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