How do small mammals respond to domestic dog olfactory cues?
Student Spotlight - Robert Black
Undergraduate Research at Newcastle University
Email: R.A.Black2@newcastle.ac.uk
Hi, my name’s Robert Black and I’ve just completed a BSc Countryside Management degree at Newcastle University. Like many of you reading this I’m a dog owner. In fact, I’ve spent a lifetime with my dogs as a Hill Shepherd in Northumberland, and probably like you, I’ve often wondered about, and been exasperated by, what goes on in their heads! Their behaviour intrigues me and having seen how my working dogs behave out in the open, I have often contemplated what effect our canine pals have on wildlife.
That’s why for my dissertation this year I worked with the Mammal Society and researchers from the University of Lincoln to find out more about how domestic dogs affect wildlife. To gain a holistic view of the more specific topic of dog-wildlife interactions, the UK public were invited to complete an online survey. Dog owners were presented with a series of questions and scenarios regarding their views, experiences, and practices whilst exercising their dogs. Secondly, a camera trap experiment at feeding stations was undertaken, examining the effect of the olfactory cues in dog urine on small mammal visitation and the time spent foraging during these visits. As the online survey is ongoing, I have opted here to focus on the latter part of my study, the camera trapping experiment.
Background
Interactions between domestic dogs and wildlife, and their impacts on both parties, remain relatively unrecorded and understudied. Although most dogs in the UK are not free-ranging, and instead are confined to a domicile, garden, or place of work, these dogs are frequently exercised on and off leash in open countryside, farmland, parkland, nature reserves, and urban green spaces. Domestic dogs could negatively impact on UK wildlife through predation, harassment, and disease transmission. Indirect cues from dogs, such as auditory (barking) and olfactory (e.g., scat, urine) cues, can also alter wildlife behaviour. For example, predator urine is high in allelochemicals called kairomones. Kairomones can be detected by prey species such as small mammals and may lead to specific behavioural changes such as supressed foraging, feeding and grooming, and/or dispersal to alternative habitats where such olfactory cues are not present. As such, we aimed to investigate how small mammals might respond to the presence of dog urine.
Methods
The study was set up at the University of Newcastle’s Cockle Park Farm, a 307-hectare mixed farm situated in south east Northumberland where two sets of four cameras were deployed. One set was deployed in an oak woodland, and the other along a hawthorn hedgerow. The location was chosen for its quiet nature - there is no official public access to this area of Cockle Park. More importantly, regular domestic canine presence was expected to be, and previously had been, almost non-existent.
Small mammals can be difficult to capture on camera traps so we used specially constructed feeding-station boxes, which housed the cameras at the rear of a baited box (see here for info in Rose Toney & Nick Littlewood's blog). Cameras were set to record 15 second video clips, with a time out of 10 minutes between triggers, to improve identification of fast-moving small mammals and facilitate recording of behaviours such as feeding and vigilance.
In each set of four camera traps, the entrances to three of the boxes were treated with one of three olfactory cues: red fox urine, roe deer urine, or dog urine. The fourth, the 'control' box was left untreated. The olfactory odours were applied by adding 2 ml of the assigned sample with a pipette to sponge strips fed into two strips of electric cable trunking on each side of the entrance to the box. The olfactory cues were replenished every third day of the field study. At the same time the bait was also replenished to minimise disturbance and human contact. The bait used was a mixture of squirrel food, suet pellets, mealworms and wild bird seed mixed on a 1:1:2:2 ratio.
Following an initial 2-week pilot study with no olfactory treatments, the two sets of traps were deployed for a period of 3 weeks between 4th and 25th of November 2021.
Preliminary results
The data gathered over the 3-week study is being used to identify how the olfactory treatments affected the behavioural responses of individual small mammal species through their visitation rates, time spent foraging and/or feeding, vigilance, and avoidance. We had lots of visitors to the boxes, like this cheeky vole:
Oak woodland results
Contrary to what we expected, the feeding station with the treatment of red fox urine, a common predator of all visiting species, registered almost two fifths of the total number of visits for the set, with 408 visits. This was almost double that of the other three treatments, which roughly registered one fifth each. What is also surprising here is that the dog urine treatment had the second highest visitation rate, despite expectations that the scent would deter visitors, fearful of a strange scent and prospect of an unknown predator.
What is also interesting is that the wood mouse visitation rate for roe deer, dog urine, and no treatment feeding stations was roughly 75% less than the visitation rate of the red fox urine station, despite being in the same habitat.
Hawthorn hedgerow results
The hawthorn hedgerow set of traps showed almost the opposite results in that the known predator, the red fox, came out lowest at 12.2% of the total visits (187 visits total), and the control had the highest proportion of visits at 40.2% of the total for the set; 616 visits from a set total of 1533 visits across all species. Still surprising though is that the dog urine station came out particularly high at 27.26% of the visits.
Next steps
Now that my thesis is complete and submitted, I'll be revisiting the data and results with help from the Mammal Society. In particular, we want to investigate if the behaviour of the small mammals visiting the boxes differs depending on treatment. We'll also be working on summarising the data from the online survey and I'm looking forward to sharing more detailed results from both aspects of the research as soon as possible!
Acknowledgements
I would like to give many special thanks to Holly Root-Gutteridge at the University of Lincoln for invaluable help input and time with designing and launching the online survey, and to Beth Smith and Charlie Le Marquand at the Mammal Society, without whose help I would never have got started let alone finished. Thank you so much.
Many thanks to Mike Robinson and Richard Bevan who were also there to lend a hand and give advice when needed. And to Guy Garrod, for everything over this last two years. Your help and support you have given me is so much appreciated.
And finally, thank you to my wonderful Fiancée, Dawn, for putting up with me, and very special thanks to Rab who supplied the pee and without whom none of this would have been possible!
