Hazing: Lessons Learned from the South Farallon Islands

Since I began working here within the OWCN, I’ve had a fascination with the hazing side of spill response. I mean come on, what a cool concept! The number one goal is to try to come up with creative ways to keep creatures out of danger. Not only are you trying to keep minimally impacted wildlife from becoming more impacted, but you’re also trying to prevent additional wildlife from becoming impacted at all. So, you come up with something you think will be “scary” enough to keep them away, but then days later you have to come up with something “scarier” so those animals don’t want to come back for the duration of the clean-up efforts. Talk about an ongoing battle of wits!

In hopes of gaining a better understanding for myself of what techniques work best, I recently read a report from the Island Conservation’s Farallon Islands Restoration Project study that looked at Hazing Western Gulls on the South Farallon Islands (Grout et al. 2013). It contains a lot of incredible information regarding the safe, yet productive, hazing and deterrence of wildlife, and I thought I’d share their findings with you all in case any of you find the concept of hazing/deterrence as cool as I do.

The purpose of this study was to test various tools that would haze, or deter, Western Gulls from the South Farallon Islands in order to reduce the risk of exposure to a rodenticide pellet. This trial was conducted between November 27th and December 15th, 2012 as this was the approximate time of year that was proposed to conduct a future mouse eradication project in which rodent bait would be placed on the islands. It was determined that this period would be ideal for the eradication as the majority of marine birds were off the islands, Western Gull numbers were low, and it was prior to elephant seal breeding season.  Prior to these eradication efforts being implemented, a study was needed to determine if hazing efforts would be effective at keeping the remaining Western Gulls on the island out of the eradication area where bait would be placed. Additionally, information was needed to understand if these tools would negatively impact other wildlife inhabiting the islands. Thus, this trial was launched! To be clear, no eradication efforts were conducted during this trial. This trial was needed to determine if such hazing tools would be useful and effective during the actual eradication, which to this day has not been implemented.

There were 19 different hazing tools tested during this study, including passive and active hazing measures. When individual tools were used to clear the gulls from an area, they would fly from the spot they were hazed from to another part of the island. Therefore, it became apparent that multiple hazing/deterrence tools would need to be used at one time so that when they were hazed from one area, they could not just land elsewhere, they would actually have to leave the island. Overall, it was determined that the greatest results are achieved when using a combination of tools at the same time such as helicopters, pyrotechnics, amplified biosonics (including birdguard devices, marine wailer, Long Range Acoustic Devices), and lasers. The most effective pyrotechnics proved to be the long range CAPA rockets, which unfortunately are no longer available. What surprised me the most was the impact of lasers. The lasers were not only used to dissuade gulls from landing but also used to clear roosting gulls and prevent them from coming back. In addition, they were effective over long line of sight distances and could be used out of the helicopter or from the lighthouse on SE Farallon, which provides a full vantage point around the islands. The biosonic devices were used to clear large areas of the islands with ease and appeared to have negligible impacts to the pinnipeds present.

Despite the consensus that the combination of sound and motion is most effective, there was one exception: effigies. When you hear the word ‘effigy’, you probably think of a plastic owl or other raptor placed on a fence post or mounted to a roof or other object. However, in this case, effigy refers to naturally deceased Western Gulls that were found on the islands. The researchers discovered that if these effigies were attached to a pole 8ft high, they acted as an excellent deterrent to prevent other gulls from coming to that area. These effigies not only deterred the gulls for a few days, but they successfully deterred them for several weeks which is incredibly uncommon when deploying hazing/deterrence devices. Other tools assessed that proved to be less effective included mylar streamers, balloons, kites, and zon guns. The mylar, balloons, and kites seemed to have little impact on gull presence and generally did not withstand the weather conditions present on the islands. The zon guns, while sometimes effective at close range, had limited use in this scenario given the pinniped presence and weather conditions.

Throughout the course of this study, hazing/deterrence impacts to other wildlife on the island were also noted. Species that were being monitored included Brandt’s Cormorants, Common Murres, Brown Pelicans, Black Oystercatchers, and other overwintering shorebirds. All of these birds were sensitive to the hazing tools used, so any of these methods used on the gulls are likely effective on these species as well. Even though pinnipeds were not the focus of this study, their behavior was monitored closely when testing hazing techniques on the gulls; therefore the researchers were able to observe that pyrotechnics, helicopters, and humans were the most disruptive, whereas Birdgard, Long Range Acoustic Device, lasers, and Marine Wailer had minimal impacts.

Thus, there are a variety of tools one can implement to effectively haze/deter various species. I believe that as long as we vary the tools we are using, we can successfully reduce the impacts to wildlife during an oil spill response. This study has provided great insight into the effectiveness of combining tools that use sound and motion to haze/deter wildlife from an area, and I hope we can effectively implement some of these ideas next time they are needed.

Speaking of which, I know there are quite a few of you out there who are interested in getting more training and experience in the hazing world of oil spill response. My personal goal for this upcoming year is to focus on OWCN’s hazing program, beef it up, and give all of you who are interested, an opportunity to receive additional hazing specific training. If you are a creative person who loves to experiment with ideas, and you think the hazing/deterrence side of oil spill response sounds like something you would like to participate in, please shoot me an email at jlhawkins@ucdavis.edu.

For more information on this study and to read the full paper, please follow this link:



Grout, D. R. Griffiths, M. Pott, R. Bradley, P. Warzybok, W. Vickers, D. Milsaps and G. McChesney. 2013. Hazing Western Gulls on the South Farallon Islands. Appendix E: South Farallon Islands Invasive House Mouse Eradication Project: Draft Environmental Impact Statement. Federal register #FWS-R8-NWRS-2013-0036http://www.regulations.gov

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