Dogs Canis familiaris have been domesticated for over 11,000 years and have been trained to perform a vast array of tasks. Scent dogs are routinely used to detect elusive animals of conservation concern as well as the presence of invasive nonnative predators. However, a recent review of studies on scent dogs for nature conservation found few peer-reviewed papers on detection of seabirds, and we suggest the potential of scent dogs for seabird monitoring is currently under-utilised. To stimulate wider consideration of the use of scent dogs for seabird monitoring we: (i) document the training, testing and performance of a one-year old Golden Retriever, to detect scent from European Storm Petrels Hydrobates pelagicus, and to differentiate between scent of European Storm Petrels and Manx Shearwaters Puffinus puffinus, and (ii) report on the field performance of a 12-year old Border Collie to detect Manx Shearwaters breeding in natural nest burrows and artificial nest boxes. We show that these individual dogs had a high success rate in locating hidden seabird targets by scent in experimental and field settings and we highlight some of the set-backs encountered during the training process, and their solutions. We show that the detection of occupied Manx Shearwater burrows is dependent on their depth and recent history of occupation. Our results highlight the potential value of scent dogs to establish the presence of particular seabird species at sites where breeding status is currently uncertain, and to map the extent of occupied areas. Further work is needed to validate the use of scent dogs to determine seabird breeding density in real-world situations, where detection probability may be influenced by nest site characteristics and breeding density. We stress the need to involve professionals in the selection, training and testing of scent dogs.

Dogs Canis familiaris have a long history of domestication, stretching back over 11,000 years (Bergstr m et al. 2020), and have been trained to perform a vast array of tasks, including protection and herding of livestock, search and rescue, assistance of the visually impaired and scent detection of a range of targets including narcotics, explosives, disease, plants and animals (Bird 1996; Gazit & Terkel 2003; Browne et al. 2006; Jezierski et al. 2016; Gerritsen & Haak 2017; Bennett et al. 2020). Canine olfactory neurophysiology is well-understood (Uemura 2015) and widely recognised to be immensely superior to human olfactory ability. In New Zealand and North America, scent dogs have been used for conservation purposes for many decades, to locate species of conservation concern, and their non-native predators (Dahlgren et al. 2012). The New Zealand Government Department of Conservation has operated a Conservation Dog Programme for many years (www.doc.govt.nz/our-work/conservation-dogprogramme, accessed 27/12/2020), to promote, manage and set the standards for the use of scent detection dogs for conservation purposes. Within Europe, the use of scent dogs is much less widespread, despite their potential for surveys of species such as Capercaillie Tetrao urogallus being recognised many years ago (e.g. Gilbert et al. 1998). A recent review (Grimm-Seyfarth et al. 2021) of over 2,400 published cases of the use of scent dogs for wildlife detection purposes found 619 employed dogs to detect avian targets, but only nine referred to the detection of seabirds. The paucity of peer-reviewed studies on canine detection of seabirds is surprising, since canine detection has been shown to be effective for species that breed in cavities and are only active above ground nocturnally (e.g. kiwis Apteryx sp. and Kakapo Strigops habroptilus). Many seabird species exhibit these same characteristics and some, such as the storm petrels, are well-known for their strong odour, which suggests that scent detection may provide an effective method for establishing the presence of nesting birds at potential breeding locations, and possibly to quantify breeding density.

The location and extent of breeding colonies of cavity-dwelling, nocturnal seabirds are often poorly known, leading to uncertainty regarding the presence of particular species at a given site. Even where the occurrence of breeding birds has been established, delimiting the extent of the breeding colony/sub-colonies (which potentially may cover vast areas in difficult terrain) is problematical, leading to large extrapolation errors in estimating population size from density of sample plots. The use of scent dogs to (i) detect the presence of a particular species at a site, and (ii) to indicate the extent of the area(s) occupied by the target species, offers considerable potential that is currently under-utilised in a European context, likely due to lack of experience of scent dog capabilities by those responsible for seabird monitoring.

Our primary aim is to highlight to the community of seabird researchers, conservation managers and statutory agencies the potential of scent dogs for seabird monitoring and to encourage further research into the efficacy and efficiency of scent dogs compared to existing methods. Here we (i) document the training, testing and performance of a one-year old Golden Retriever to locate targets treated with scent of European Storm Petrels Hydrobates pelagicus (hereafter Storm Petrel) in a variety of experimental settings, and (ii) quantify the reliability of a self-trained 12-year old Border Collie sheepdog to detect occupied Manx Shearwater Puffinus puffinus (hereafter Shearwater) nests in natural and artificial nest sites. We examine the dog’s assessment of Shearwater burrow occupancy in relation to burrow depth and the number of Shearwater occupants and the local occurrence of European Rabbits Oryctolagus cuniculus (hereafter ‘Rabbits’), which may all influence scent detection. We document problems, set-backs and solutions, and quantify the relative time effort required for canine scent detection compared to conventional survey methods, acknowledging that many of these issues would not have arisen had we employed fully-trained dogs and professional handlers. We hope that our study will encourage others to consider the use of scent dogs for seabird monitoring, under professional guidance and to conduct appropriate assessment of precision and sensitivity of scent dog performance.

We thank Sally Sanford for stimulating discussion on the potential of scent dogs for conservation monitoring and for demonstrating scent dogs in action. We also thank two anonymous reviewers for helpful comments on an earlier draft of this paper.

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Comparison of binomial errors models [PDF]