Bait delivery for cats using drons

Johnston, M., McCaldin, G., & Rieker, A. (2016). Assessing the availability of aerially delivered baits to feral cats through rainforest canopy using unmanned aircraft. Journal of Unmanned Vehicle Systems, 4(4), 276-281.

At least eight threatened wildlife species are at direct risk from predation by cats (Felis catus) on Christmas Island (Director of National Parks. 2014. Christmas Island biodiversity conservation plan. Canberra. Australia: Department of the Environment.). A range of strategies are now being used to manage cats across the island, including responsible ownership methods for domestic cats and lethal control tools to remove feral cats outside the township area. Unmanned aerial vehicles (UAVs) were used to drop non-toxic baits through the rainforest canopy to assess whether aerial baiting could be undertaken successfully on the island. Ground crews located 88% of baits, indicating that sufficient baits would be accessible to feral cats if broad-scale aerial baiting was to be undertaken in the future.

Potential use of attractants for feral cats

Scaffidi, A., Algar, D., Bohman, B., Ghisalberti, E., & Flematti, G. (2015). Identification of the cat attractants isodihydronepetalactone and isoiridomyrmecin from Acalypha indica. Australian Journal of Chemistry.

Acalypha indica is a herb that grows throughout the tropical regions of the world. As well as being exploited for medicinal use, the roots of this plant are known to elicit a drug-like effect on cats. Recent research into feral cat control on Christmas Island has investigated whether a preparation of the roots of A. indica might be effective in traps to attract feral cats. However, the volatile nature of the attractants made it unviable for use in traps for more than a few days. In this study we investigated the volatile components emitted by the plant roots and identified two iridoid compounds, (4R,4aR,7S,7aR)-isodihydronepetalactone and (4R,4aS,7S,7aR)-isoiridomyrmecin, which are known to affect behavioural activity in cats. Synthesis of standards confirmed the stereochemistry of both compounds emitted by the plant. Potential application for these compounds in feral cat control is discussed.

Ecological Restoration of sub-Antarctic Macquarie Island

Springer, K. Ecological Restoration of sub-Antarctic Macquarie Island.

Invasive vertebrate species have had devastating impacts on the flora, fauna and landforms of Macquarie Island over a period of 200 years. Following the successful eradication of weka (Gallirallus australis) by 1989 and feral cats (Felis catus) by 2001, planning for the eradication of ship rats (Rattus rattus), house mice (Mus musculus) and European rabbits (Oryctolagus cuniculus) began in 2004. Funding of AUD$24.7M was secured in 2007 for a multi-year project based on aerial baiting targeting rabbits and rodents followed by ground hunting targeting surviving rabbits. The first aerial baiting attempt in 2010 was abandoned due to unfavourable weather and shipping delays. The degree of non-target seabird species mortality from limited baiting in 2010 lead to a renewed examination of non-target mitigation options. Rabbit Haemorrhagic Disease Virus (RHDV) was introduced in February 2011, to reduce the pre-baiting rabbit population and thus minimise non-target mortality amongst scavenging seabirds. Aerial baiting resumed in May 2011 using four AS350 helicopters and a team of 27 people, and was completed by July 2011. No rodents have been detected post-baiting and the estimated rabbit population of 150,000 has been reduced to fewer than 30 at the conclusion of baiting The rabbit hunting phase commenced in July 2011 using a team of 15 hunters and 12 dogs and is ongoing, with thirteen rabbits accounted for. Hunting and monitoring is expected to take a total of five years post-baiting and will be based on annual progress reviews. A minimum of two years monitoring will be conducted. Rodent detection dogs will deploy in 2013 to assist in determining rodent eradication success.
Six months after baiting, vegetation recovery was already evident and increased burrownesting seabird activity has also been observed in the first breeding season post-baiting.

Attracting feral cats and other alien predators

Read, J. L., Bengsen, A. J., Meek, P. D., & Moseby, K. E. (2015). How to snap your cat: optimum lures and their placement for attracting mammalian predators in arid Australia. Wildlife Research, 42(1), 1-12.

Context: Automatically activated cameras (camera traps) and automated poison-delivery devices are increasingly being used to monitor and manage predators such as felids and canids. Maximising visitation rates to sentry positions enhances the efficacy of feral-predator management, especially for feral cats, which are typically less attracted to food-based lures than canids.

Aims: The influence of camera-trap placement and lures were investigated to determine optimal monitoring and control strategies for feral cats and other predators in two regions of semi-arid South Australia.

Methods: We compared autumn and winter capture rates, activity patterns and behaviours of cats, foxes and dingoes at different landscape elements and with different lures in three independent 6 km × 3 km grids of 18 camera-trap sites.

Key results: Neither visual, olfactory or audio lures increased recorded visitation rates by any predators, although an audio and a scent-based lure both elicited behavioural responses in predators. Cameras set on roads yielded an eight times greater capture rate for dingoes than did off-road cameras. Roads and resource points also yielded highest captures of cats and foxes. All predators were less nocturnal in winter than in autumn and fox detections at the Immarna site peaked in months when dingo and cat activity were lowest.

Conclusions: Monitoring and management programs for cats and other predators in arid Australia should focus on roads and resource points where predator activity is highest. Olfactory and auditory lures can elicit behavioural responses that render cats more susceptible to passive monitoring and control techniques. Dingo activity appeared to be inversely related to fox but not cat activity during our monitoring period.

Implications: Optimised management of feral cats in the Australian arid zone would benefit from site- and season-specific lure trials.

Response of feral cats to a track‐based baiting programme

Doherty, T. S., & Algar, D. (2015). Response of feral cats to a track‐based baiting programme using Eradicat® baits. Ecological Management & Restoration, 16(2), 124-130.

The feral Cat (Felis catus) is a significant threat to Australian fauna, and reducing their impacts is considered an essential action for threatened species conservation. Poison baiting is increasingly being used for the broad scale control of feral cats. In this study, we measured the population response of feral cats to a track-based baiting programme using Eradicat® baits in the semi-arid northern wheatbelt region of Western Australia. Over two years, 1500 baits were laid once annually and the response of feral cats was measured using remote cameras in a before–after, control–impact design. There was a significant reduction in feral cat activity in the second year, but not the first. During bait uptake trials, corvids removed the most number of baits, followed by cats and varanids. The lack of a response to baiting in the first year may be due to existing low cat numbers in the baited area and/or the timing of the baiting. We provide a list of key recommendations to help inform future cat baiting programmes and research.

Bait preference testing for rabies oral vaccination

Berentsen, A. R., Bender, S., Bender, P., Bergman, D., Hausig, K., & VerCauteren, K. C. (2014). Preference among seven bait flavors delivered to domestic dogs in Arizona: implications for oral rabies vaccination on the Navajo Nation. Journal of Veterinary Behavior: Clinical Applications and Research.

Less than 20% of domestic dogs on tribal lands in the United States are vaccinated against rabies. One method to increase vaccination rates may be the distribution of oral rabies vaccines (ORV). ONRAB^® is the primary ORV bait used in Canada to vaccinate striped skunks and raccoons. To investigate the potential use of ONRAB^® ORV baits to vaccinate feral domestic dogs against rabies on tribal lands and beyond, we performed a flavor preference study. Seven bait flavors (bacon, cheese, dog food, hazelnut, sugar-vanilla, peanut butter and sardine) were offered in pairs to 13 domestic dogs. Each dog was offered all possible combinations of bait pairs over a period of ten days, with each bait offered six times. The proportion of times each bait was consumed first by individual dogs was calculated and comparisons among dogs were conducted using the MIXED procedure in SAS. Pairwise comparisons between baits were performed using “contrast” statements with sugar-vanilla flavor as the default for comparison. Type three tests of fixed effects showed a significant treatment effect (F_6,72 = 9.74, P < 0.0001). Sugar-vanilla was selected first during 14% of offerings and exhibited the least preference among all bait types (F_1,72 = 22.46, P < 0.0001). Dog food was selected first 56% of the time, and more frequently than all other bait types (F_1,72 = 13.09, P = 0.0005).

Curiosity bait field essays

Johnston, M., Bould, L., O’Donoghue, M., Holdsworth, M., Marmion, P., Bilney, R., Reside, A.E., Caldwell, D., Gaborov, R.  & Gentles, T. (2014). Field efficacy of the Curiosity® bait for management of a feral cat population at Roxby Downs, South Australia. Arthur Rylah Institute for Environmental Research Technical Report Series, (253).

The management of feral cat (Felis catus) populations over large areas in Australia is currently limited by a lack of cost-effective control techniques. Existing techniques, including trapping, shooting and fencing when used to manage large areas are limited by their significant cost. The distribution of poison baits can provide a lower-cost alternative but must address the hazard that the surface-laid baits may present to non-target species. The Eradicat^® bait was developed for application in areas where native wildlife have a high tolerance to the poison, sodium monofluoroacetate (1080), used in this product. This bait is generally unsuitable for use in other areas, such as eastern Australia, where native species have a lower tolerance to 1080.

The Australian Government has funded the development of an alternative poison bait for feral cat

control that is a based on Eradicat®. This bait, Curiosity®, exploits differences in feeding behaviour between feral cats and non-target species by presenting the toxicant, para-aminopropiophenone (PAPP), in an encapsulated pellet.

This trial was part of a series of field trials conducted across Australia to assess the efficacy of this bait product and will contribute to the data submitted for product registration purposes. Curiosity® baits were aerially distributed over a 430 km2 area within Roxby Downs Station, South Australia, in July 2013. Monitoring of the bait efficacy program was undertaken using several methods. The survival of eighteen cats trapped within the baited area was monitored with radio transmitting collars. Site occupancy of feral cats was assessed prior to, and following baiting, using automated cameras at 68 sites. Counts of cat activity on 14 groomed track plots were also recorded.

Ten of the collared cats (58%) were confirmed as having died following consumption of Curiosity® bait(s). The GPS data recovered from the seven cats that survived baiting indicated that they all should have encountered bait(s) during the 10 day period following bait distribution. However, only one of these cats was confirmed to have consumed a bait. One cat was discounted from collar return statistics as its survival after baiting could not be determined. There was a statistically significant 52% reduction in the occupancy estimates of feral cats after baiting, consistent with the collar return data. However, the data from track counts did not indicate any change in the cat population although this aspect of the study was compromised by wet weather and site access difficulties. It is also probable that the low number and location of plots affected the results observed in the track count component of the study.

The study also included replicated counts of birds prior to and post baiting to determine whether the Curiosity® baits led to a decrease in populations of non-target species. A 50% decrease in the counts of corvid species was observed in the post-baiting monitor period while other non-target species did not decline. It is not possible to wholly associate the apparent decline in corvids with use of the Curiosity® baits as other factors, such as migration or count error, may have contributed to this result. Rejection of the encapsulated toxicant pellet was observed on one occasion and was attributed to bait consumption by a corvid. No carcasses of wildlife species were encountered during the study that implicated Curiosity® baits as the cause of death.

Some further development is required to prevent the premature loss of structural integrity of the Curiosity® coating structure, and thus leakage of the toxicant formulation material from the delivery device. Despite this, the results from this study indicate that the Curiosity® bait reduced the feral cat population at this site.