1 Good Nature © piston trap trial on farms in Delta Fall 2020/Spring 2021 Written by Sofi Hindmarch 2 Table of Contents Acknowledgement ................................ ................................ ................................ ................................ ........ 3 Executive Summary ................................ ................................ ................................ ................................ ....... 3 Introduction ................................ ................................ ................................ ................................ .................. 4 Methods ................................ ................................ ................................ ................................ ........................ 5 Study Area ................................ ................................ ................................ ................................ ................. 5 Piston Trap Trial ................................ ................................ ................................ ................................ ........ 6 Results and Discussion ................................ ................................ ................................ ................................ .. 9 Deer mice attracted to the piston traps ................................ ................................ ................................ 10 Non - target species attracted to the piston trap ................................ ................................ ..................... 12 Case Studies: ................................ ................................ ................................ ................................ ........... 13 Example one – Hobby hen farmer who implemented preventive actions during the trial. ............... 13 Example two – Certified organic vegetable and egg farmer was able to curb the rat infestation after the hens had left the coop. ................................ ................................ ................................ ................. 15 Example three – Preventive measures not followed. ................................ ................................ ......... 17 Lack of pr eventive measures and misapplication of anticoagulant rodenticides ................................ .. 19 Conclusion ................................ ................................ ................................ ................................ ................... 20 Literature Cited ................................ ................................ ................................ ................................ ........... 21 3 Acknowle dgem ent This project was made possible with funding provided by Environment and Climate Change Canada The support of the local farmers in Delta was critical to the success of this project. I am very grateful to the farmers who allowed me to access their p rope rties to trial the piston traps. Executive Summary Secondary rodenticide poisoning of raptors, includ ing species at - risk, is an ongoing issue in s outhern British Columbia. Controlling rodents using non - toxic options would reduce the amount of rodentic ides applied on the landscape and ultimately reduce the risk of exposing non - target species. The intent of th is project was to assess the viability of using the Goodnature © piston trap to control rats on farms. The tria l was conducted on 10 farms in Delta, Bri tish Columbia between October 2020, and February 2021. T he piston traps were deployed at nine of the t en si tes after documenting the presence of rodents using the Goodnature © lure. Of these nine sites, the piston trap was successful at trapping rodent s at eight sites At four sites rats were huma nely destroyed and at the o ther four sites deer mice were trapped. A t site nine , video monitoring only documented feral cats, i.e. , no rodents were triggering the camer a s or the traps The video monitor ing documented non - target species attracted to the trap s w hen the p ist on trap s we re placed outdoor s It is therefore recommended that the Goodnature © blocker be used when the trap s are placed outdoor s along the perimeter of buildings or fenceposts. The pisto n tr aps were most effective at farms where preventive measures were being followed, such as removing food sources and shelter for the rats. The preventive aspect is impe rative for the success of any rodent control and was an important outreach message as p art of this project. At farms permanently using rodenticides, misapplica tion and lack of preventive measures were documented This highlights the ongoing need to work with pest control operators, vendors and farmers provid ing education on the pr oper use of rod enticides 4 Introduction Rodents are a group of pests that are notoriously known for damaging crops and stored grained , in particular in developing countries but also industrialized ones with significant agricultural exports (Ged d es 1 992 ; Stenseth et al. 2003; Singleton 2003 ; Jacob and Buckle 2018 ) The primary method for controlling rat infestations worldwide, including within the agricultural sector, is through the use of an ticoagulant rodenticides (ARs) (Corrigan 2001; Dawson et al. 2004; Lima and Sal mon 2010; Jaco b and Buckle 2018 ) The first generation anticoagulant rodenticides (FGARs: warfarin, diphacinone, and chlorophacinone ) were introduced commercially in the 1940s, and since then, their widespread use has led to genetic resistance in some rod ent populations ( Boyle 1960; Buckle et a l. 1994 ; Berny et al. 2018 ) S econ d generation anticoagulant rodenticides (SGARs: brodifacoum, bromadiolone and difethialone) , introduced in the 1970s, are considerably more toxic, persistent and bio accumulative compared to FGARs, and are capable of killing target rodents after a singl e fe eding (E ason et al. 2002; Fisher et al. 2003) . Currently, SGARs are the most widely used compounds, especially by professional rodent contro l op erators and farmers (Corrigan 2001; Elliott et al. 2016 ; Hindmarch et al. 2018 ) Annual sales of rodenticide products are projected to surpass one billion dollars this year (Zion Market Researc h 20 21 ). The toxic and persistent nature of SGARs and their widespread us e has had consequences beyond controlling rodents. Exposures and poisoning of non - target wildlife, particularly the secondary poisoning of raptors is increasingly being documented wor ldwide ( E ason et al., 1999, 2002 ; Ston e et al. 1999; Brakes 2005; Riley et al. 2007; Walker et al. 2008; Albert et al. 2010; Murray, 2011 , 2020 ; Thomas et al., 2011 ; Chr ist ensen et al. 2012 ; Nakamaya et al. 2018 ) S econdary exposure of raptors has also been well documented in the Fraser River Delta in southwestern British Columbia (Albert et al. 2010; Elliott et al. 2014; Huang et al . 2016). During the mid - 19 th century, t he low - lying lands in the regi on w ere diked an d convert ed to agricultural fields that were primarily used for pasture and hay production However, d uring the past 6 0 years, significant amounts of farmland ha s been converted to greenhouse vegetable production and berries (Elliott et al. 2011; Metro Vancouver 2012) Both crop types require more intensive rodent control tha n grass fields to ensure that plants and produce are not damaged when being produced and stored Since 2008, vegetable farmers and greenhouse facilities are obligated to maintain rodent control programs as part of government a dministere d food safety standards (CanadaGAP 20 21 ) Hindmarch et al. (2018) surveyed farmers in Delta, British Columbia and found that 94% of farmers applied ARs to control rodents, of which 37% were appl ying SGAR s permanently as part of their food safety program. Consequently, barns processing vegetables and greenhouses are often permanently baited with the SGAR bromadiolone along the outdoor perimeter. The Fraser River Delta agricultural landscape is home to several listed predators such as barn owls ( Tyto furcat a ) , long - eared owls ( Asio flammeus ) , and great blue herons ( Ar d ea herodias ) , all of which depend on rodents as a key food source. Barn owls in particular are closely tied to the agricultural landscape and nest inside barns , riding arenas or other barn structures . They were recently upgraded to threatened in s outhwestern British Colu mbia, primarily due to the loss of habitat , but AR exposure/toxicosis is identified as a threat to the western population of barn owls (SARA 20 1 8 , COSEWIC 2010 ). Hua ng et al. 5 (2016) showed that barn owls sampled between 2006 – 2013 had significantly higher AR re sidue concentration when compared to individuals sampled in 1992 – 2003. Barn owls and other raptors are rodent specialists and can be the farmers’ allies in co mbatin g rodent problems , hence there is a need to find rodent control methods where raptors can be part of an integrated pest management solution , without the risk of being poisoned Ensuring that non - toxic control options are considered first, an d rodenticides are only used as a last resort will help reduce this threat The objective of this trial was to assess the effectiveness of using a non - chemical, instant kill, self - resetting piston trap ( A24 Goodnature © t rap ) on farms in Delta, BC. The p iston trap works by shooting a CO 2 powered piston into the head of a rodent that climbs inside the trap The rodent triggers the piston when trying to eat the lure inside the cap of the trap and once dead will drop down to the ground where it can be sa fe ly scavenged by ot her animals. The trap automatically resets and can trigger up to 24 times on one CO 2 - cylinder. Specifically, this trial will evaluate : • whether piston traps can reduce the damage and presence of rats on farms, • the most effective way to install and attr act rats to the piston trap, and • r isk of non - target byca tch Methods S tudy Area I conducted the trial in Delta, British Columbia, a municipality that has been one of the main areas where raptors have been tested routinel y for ARs sinc e the early 2000s (Albert et al. 2010; Huang et al. 2016) . Delta lies at the mouth of the Fraser River and consists predominantly of low - lying floodplains, with some forested areas furthe r inland (Fig. 1). In the 1850s, E uropean immigrants settled in the area and claimed land for farming by diking the foreshore (North and Teversham 1983) . Delta is also recognized as an important bird area, as it includes some of th e main stop - ov er sites for birds mi grating on the Pacific flyway (Important Bird Areas 20 21 ) . Further, important wildlife areas such as the Alakse n National Wildlife Ar ea, Burns Bog and Boundary Bay provide vital year - round habitat for resident raptors and overwintering birds. However, low lying productive shoreline habitats often face strong development pressures (McKinney 2002) , and Delta is no exception. Ongoing infrastructure and housing projects continue to encroach on and fragment t he land, making it less v iable for farming. Development pressure and speculation has also increased the cost of land and triggered a shift from traditional grassland - associated agriculture to more intensive cash crops such as greenho use and berry product ion, which has result ed in less grass vegetation , and therefore decreased habitat for raptors ( Metro Vancouver 2012) 6 P iston Trap Trial The piston trap (aka A24) was developed by the New Zeala nd company Goodnature © in 2011 , with the intent of providing a huma ne and toxin free control option for invasive rats and possums in New Zealand (Fig 1 ). The company has expanded its operations and has currently distributors in North America, Europe and Australia , in addition to New Zealand. Figure 1 . The Goodnature © r odent trap works by attracting the rat to the trap using a long - life rodent lure. To access the lure, the rat triggers a sensitive pin (in red) that sets the trap in motion and a CO 2 pressurised piston (in orange) stri kes the rode nt’s head killing it insta ntly and then retracts on a light spring. The dead rodent falls to the ground and the trap automatically reset s itself ready for the next rat to arrive. In total 20 piston traps were installed on farms in Delta and mo nitored weekly. The sites chosen were not currently using rodenticides, but five had previously deployed rodenticides and two farms were using snap traps during the trial. The deployment of the piston traps fo llowed the recommendation s set by G oodnature © The initial step was to identify wher e the rats fe lt comfortable eating. Unlike rodenticides placed inside a bait station, the piston traps do not provide the rat with an enclosed and safe area to ea t. Goodnat ure© recommends pre - applying their long - life l ure ( toxin - free, tastes sweet and smel ls of chocolate ) in several locations so you can identify where a rat feels comfortable eating The piston trap kit comes with six small lure packs that can be installed in and outside structures where there is evidenc e of rats (i.e., rat tunnel openings , feces, gnawing and damage to structures ) At each farm site lure packs were installed at 5 - 6 locations and monitored weekly for uptake (Fig 2 ). Lu re packs that had been completely eaten were replaced with piston traps . The traps were not initially set, bu t lure was added in the lure cap and added in small portions next to the piston trap to continue to get the rats interested in the lure and comfort able with the traps (Fig 3 ) . After 1 - 2 weeks of lure baiting the 7 piston traps were set , and lure w as only applied to the b ase of the trap and inside the lure cap. To create a sense of safety for the rats, I would in some locations place a small piece of plywood on an angle over the lure and the piston traps (Fig 4 ). A selected 2 - 3 lure packs or trap s at each site were monitored with wildlife camera s to help determine the presence of rats and the behaviour exhibited by rats at the traps. The vi deo monitoring also allowed me to assess whether non - target animals wou ld access the traps. The cameras were set to record for 10 seconds when triggered with a 10 second rest period in between. Figure 2. Lure pack on post 8 Figure 3. Piston trap set - up with camera. Figure 4. To provide the rats with a sense of securi ty, I placed a small piece of plywood over the lure pack or piston trap in exposed locations. This also prevented hens from pecking on the equipment. 9 Results and Discussion B etween October 2020 and February 2021, the trial was conducted on 10 farms in De lta ( six livestock f arms, three vegeta ble / berry farm er s, and one equestrian facilit y , with hens for their own egg consumption The farmers that were interested in participating had experienced (n=6) or were currently dealing with a severe rat infestation o n their farm ( n=4). Nine of t en ide ntified farms were suitable for trap deployment At the 10 th site , the farmer follow ed preventive measure s such as ke eping the perimeter of the barn clean, and the barn was currently being used for equipment storage , so there were no food attractants in the barn N one of the lure pack s were chewed and there were no signs of rodents At all sites, rats where the main pest rodent, however, at five sites the farmers would also cont rol for mice when needed. In total, t he piston traps were triggered by rats at four farms ( n=19) , all of which were placed inside hen co o ps and d eer mice triggered the piston traps at another four farms (n=1 4) At one farm, none of the piston traps were set off and th e camera was only triggered by feral cats ( Table 1 ). The video foot age did confirm cannibalism by both deer mice and rats (Fig 5 ). Figure 5 . Cannibalism was documented by both rats and deer mice , as depicted on this picture, a deer mouse is eating a de ad conspecific. 10 Deer mice attracted to the piston traps The video monitoring showed that deer mice did not hesitate to eat the Goodnature © lure and enter the piston trap, demonstrating that the trap was also effective at controlling for deer mice. In general, at sites where both rats and deer mice were present , the mic e were more frequently seen eating the lure on video footage than rats and were more commonly observed entering the piston trap (Fig 6 ). Initially, t he piston traps were triggered by deer mice at two sites Therefore, I removed the set piston traps , as d eer mice were not a target species at either farm. Howe ver, I cont inued video mon itoring at the site s with piston traps that were not set , to see whether other non - targets were attracted to the trap. To prevent deer mice, songbirds and other non - targets fr om enteri ng the trap s I trial led the A24 blocker , which is intended to prevent non - targets from entering the piston trap. However, video monitoring of the piston tra ps wi th the blocker showed that the deer mice were not deterred from entering the trap. Th e blocker seemed to prevent grey squirrels and possums, and would, as suggested by Goodnature © , also prevent smaller pets from entering the traps. There was one farm site where deer mice were an issue, as they were getting inside the barn where vegetables were being stored, and one piston trap placed strategically by the cold storage unit killed 10 deer mice over a four - week period. As a sid e note , post deployment, som e of the traps that were set and could not be disarmed due to pressurized CO 2 inside the trap , were stored in a cardboard box in my garage Within two days of being stored, t h ree deer mice had found their way into the b ox and triggered two of the t hree traps Fig ure 6 . Deer mouse eating the lure around the piston trap. Deer mice were less hesitant than rats to enter the piston traps and were more frequently seen on video footage compared to rats. 11 Table 1. Summary of sit es where the piston trap tr ial was co nducted and the number of rats and deer mice that were humanely destro yed using the piston trap. Site Type Piston Traps Deployed Rats Deer Mice Preventive measures 1 Comments 1 Vegetables Yes 9 0 Somewhat 2 Vegetables Yes 0 10 Good 3 Vegetable s & Berries Yes 1 Not followed 4 Equestrian and Hens/Eggs Yes 2 0 Implementing 5 Dairy Yes 0 0 Somewhat No rodents documented on camera 6 Hay Yes 0 2 Not followed 7 Hens/Eggs Yes 4 0 Good 8 Hay Yes 0 1 Not followed 9 Hens/Eggs Yes 4 0 Implementing 10 Cows No 0 0 Good No lures eaten SUM 1 9 14 1 Categories: Not followed, somewhat, good, i mplementing 12 Non - target species attracted to the piston trap Video monitoring documented other non - tar get spe cies attracted to the lure in the piston trap. For example, a grey squirrel and a possum were seen eating the lure In both instances, the blocker prevent ed the larger mammals from entering t he piston trap (Fig 7 ) . A t one site, a winter w ren was seen on several occasions around the p iston trap and at another site a song sparrow N either species w as observed eating the lure. However, a concurrent project trialing the piston traps in berry fields did document a junco being humanely destroyed when the attractant in the piston trap was peanut butter. As songbirds and other mammals might enter the piston traps, I would recommend using the blocker when the trap is placed out doors along the perimeter of buildings or on fenceposts Figure 7 . Video footage of non - target species see n around the p iston trap (i.e. , winter wren and song sparrow) or eating the Goodnature © lure (i.e. , grey squirrel and possum ) . Clockwise from top left: w inter wren, grey squirrel, pos sum, song sparrow 13 Case Studies: Example one – Hobby h en f arm er wh o i m plement ed preventive actions during the trial. The far mer ha s laying hens for personal egg consumption and local sales and had never had any previous problems with rats until the fall of 2020. The rats were getting into the hen co o p and che wing their way into other parts of the barn. The farmer was initia lly using a bromadiolone rodenticide product to control the rats, but the rats were not eating the bait. During my initial site visit, I recorded several large burrows dug by the rats along the perimeter o f the hen co o p , providing the rats w ith easy access to the fenced outdoor area for the hens . Fortunately, the farmer was already in the process of implementing various preventive measures such as blocking entry points into the barn area where the hens were fed and locked up overnight with me tal sheeting This prevented the rats from entering the barn and having access to the hen food overnight I installed five lure cards during my initial site visit, an d after two weeks all the lure cards were completely e a ten (Fig 8 ) . I subsequently installed three piston traps at locations where the chew cards had been eaten, but did not set the traps, and continued pre - baiting the traps with the lure as recommended by Goodnature © . Rats are neophobic and w ary of new thing s in their environment, so continuing to pre - bait the piston traps would allow the rats to get used t o and comfortable eating from the piston traps. After ten days the traps were set, and four rats wer e killed the first week of deployment. On the firs t nig ht of deployment t he camera footage revealed that one rat carcass was removed by another rat , 30 minutes after it had been killed (Fig 9 ). It is i nteresting to note that no more rats were killed after the initial week of deployment, even though rats were s till detected on the cameras. We also tried baiting the piston traps with the hen food, as this was a food source the rats were familiar with, but none of the piston traps were trigger ed Regardless , the farmer did find that the rats were now manageable an d continued to ensure that the rats were not able to access the inside of the barn. W e removed the piston traps two months after initial deployment. Fig ure 8 . The chew card s were completely eaten after two weeks and the he ns we re more than happy to help w ith the deployment of the piston traps. 14 Fig ure 9 Rat killed the evening the piston traps were set, dead rat was dragged away from trap site 30 minutes after it was kill ed, and new rat emerges 15 Example two – Certifi ed organic vegetable and egg farmer was able to curb the rat infestation after the hens had left the coop The farm is a certified organic vegetable and egg farm. The rats had been an issue in the hen coop for the last three months , and t he y had m anaged to get inside the walls and eaves resulting in them eating spilled food at night (Fig 10 ) . The farmer was actively trying to trap the rats an d had some success with snap traps, but not enough to curb the infestation. Fig ure 10 . Camera footage docum ented that the rats were getting inside the hen coop at night eating spilled food. Three rats can be seen in this picture. Only two of the six lu re cards were eaten after they had been in p lace for a week , but this helped guide the installation of two pis ton traps , each monitored with a camera. The piston traps were set when they were initially installed, as this was prior to my conversation with G oodnature © about pre - baiting the piston traps before setting them (i.e., to get the rats used to the trap and comfortable eating inside the trap where the metal pin that trigger s the trap is located) . The camera revealed that there were lots of rats around , one came ra had been triggered over 600 times in two weeks, often documenting two or three rats during the 10 second recording interval. The rats were eating the Goodnature © lure around the trap but did not want to enter inside the piston trap, and cons equently n either trap had been triggered. The rats ’ hesitancy to enter the piston traps could also be explained by the fact that there was a lot of spilled hen feed available to them inside hen coop , and hence no incentive for them to further 16 investigat e the pist on traps. However, this changed two months post deployment, as the hens were culled on December 22 nd , 202 0 and the hen coop was left empty. The rats started to enter the piston traps January 10 th onwards and a total of nine rats were killed ov er a three - week period (Fig 11 ) . The farmer also noted an uptake in snap traps during th e same period and as of mid - Fe bruary no more rats were seen in the hen coop and the traps were removed. The intent is to have a new batch of hens in the coop in th e future, so I highly recommended that this would be a good time to perform preventive actions such as sealing up the eaves and walls, making the hen coop rat pro of . This will reduce the likelihood of a future rat infestation and make it easier to trap rats that are trying to access the coop Fig ure 11 . After the hens were culled and there was no more hen feed the rats sta rted to take to the piston traps with a total of nine rats killed in a three - week period 17 Example three – Preventive measures not followed Th is site is an equestrian facility with a small hen flock for own egg consumption. The facility was currently ex periencing a rat infestation in the room they stor ed horse feed and in the hen coop . On my initial site visit I noted that th e rats had easy access to the horse feed room during the day when the door was open, but camera footage also revealed that the rats were able to access the room at night (Fig 12 ) . The horse food was stored in plastic and metal containers but there was spill age providing the rats with a n abundant and desirable food source. There was a similar situation in the hen coop , as the hens were feed outside in a fenced area and rats were observed eating alongside the hens in the daytime and the re were several rat t unnels and burrows underneath the hen coop (Fig 13 ) . I do not think the rats had access to the hen house where the hens slept overnig ht, but in all likelihood the spillage of hen food in the fenced day coop provided the rats with sufficient food overn ight. Figure 12 The rats were able to acces the horse feed room and rat f eces was observed on shelving , and the presence of rats w as als o confirmed on camera footage. I install ed five lurecards in the horse feed room and four in the hen coop . Interestingly, throughout the trial period none of the lurecards p laced in the horse feed room were chewe d. T he video monitoring documented at leas t three rats, but the ab undan c e of spilled horse feed provided the rats with ample food options, and no incentive to try out the lure cards. The four lure c ards placed in the hen coop were all eaten in one week, and four pis ton traps were installed in the fen ced area of the hen coop . Two rats were killed in a two week period , but then there was no uptake and rats were still seen in the daytime and on video f ootage taken at night. During this trial period none of the preventive measures were introduced, and the rat infestation is ongoing. I discussed preventive options with the owner, such as rat proofing the horse feed roo m, and options for reducing the spillage of hen feed. S he was considering implementing some of these measures in the near future. 18 Fig ure 13 Rat eating spilled hen food in fenced area of hen coop alongside songbirds. 19 Lack of preventive meas ures a nd misapplication of anticoagulant rodenticides Rat control is most effective and sustainable if preventive measures such as removal of food sources, litter and rat proofing structures ar e implemented before any form of rodent control is conducted ( Co rri gan 2001: CRRU 20 1 5 ). However, in many instances, preventive actions intended to reduce the carrying capacity of rats in the environment were not condu cted prior to rodent control. During this pilot project, I document ed three instances where rodenticides had been app lied . Two of which were not following best management practices At the first site , which was managed by a professional pest control compan y , adequate preventive actions were not implemented (Fig 14 ). The second site had an ongoing rat infestation and the land owner had purchase d a bucket of a rodenticide product that was for indoor use only (active ingredient: bro di f acoum ) but was recommended by the vendor to use this product to control rats outside. Lack of preventive actions both by landowne rs a nd hired pest control operators, and misapplication of rodenticides has been previously documented in Delta (Hindmarch et al. 2018). Fig ure 14 . Bait station seen in background, which was serviced bi - weekly by pest control operator but no preventive acti ons such as removal of litter and rodent proofing structures was conducted. 20 Conclusion Overall, the piston traps were triggered at eight of the nine s ites they were deployed, and no rats or deer mice were documented at the ninth site. The most important fact or to increase the success of the piston traps was to ensure that preventive measures were followed, such as removing food sources and shelter for t he rats. Rats are neophobic and will not try new food sources if they already have a steady supply of fo od available to them through familiar and easily accessible stored/spilled animal feed or food waste ( Fig 15 ). This was also apparent from this study, a s in all cases t he success ra te of trapping rats increased when food sources and hiding pl aces were eliminated The most successful trap sites had e x c lu ded rats from entering the hen coop , or the hen food was no longer available to the rats. The st udy demo nstrated that piston trap s were also effective when controlling for deer mice. B ased on our video monitoring they were the most frequently documented species eating the Goodnature © lure and entering the piston trap a t farms where rats were also pre sent. Fig ure 15 . Rats will not be interested in the Goodnature © lure pack as seen here fastened to the side of this pallet if they already have a safe and proven food source in easily accessible animal feed. Non - target species such as squirrels, possums and song birds might be attracted to the piston trap if they are installed out doo rs along the p erimeter of buildings or fenceposts. In such cases, I would highly recommend using the Goodnature © blocker on the piston trap as this will discourage non - target species, including pets from entering the trap. As has been previous docu mented in this region (Hindmarch et al. 2018) , anticoagulant rodenticides were in some cases permanently used as a first line of defense against rodents At one site, preventive measures suc h as removal of litter and rodent proofing the structure were lacking , which was con cerning given that the site was managed by a professional pest control operator. Applying indoor only products out doors was also documented at another site where spilled an imal feed was readily available for the rats. These examples poin t to two ongoin g challenges : ensuring that preventive