If you saw the now familiar orange safety vests and a man
carrying what looks like a rifle (he’s a wildlife veterinarian and it’s a dart
projector!) you’ll know that our field team was once again out in the field
The purpose of the fieldwork was two-fold. One was to check the fit of the collars
placed on 40 does in the Fall of 2019. The
second purpose of being in the field this winter/spring was to re-mark a
Because we were out in the field again to capture a control
group, we used the opportunity to double-check on collar fit. There were some concerns voiced from the
community that the collars used to identify does that have received
immuno-contraception are too tight, and we have been following those concerns
up diligently. We checked on many of the
does that were specifically reported to us since September with concerns of a
too tight collar, and Dr. Hering, our wildlife veterinarian, was able to report
that in fact the collars are fitting well. Nine does were re-captured, their
necks re-measured to look for growth and that the collars are not causing any
problems. None of the collars that were checked are fitting too tightly or
appear to be causing the animals any problems and so it was not necessary to
replace or remove any collars because of inappropriate fit. The fit is very
similar to that of a dog collar on a dog, which is what he was aiming for. However the collars can appear to fit tighter
than they actually are, due to winter fur growth.
Although from a distance it can look as though a collar is
too tight, when you’re up close it is much easier to tell how much room there
actually is under the collar. Dr. Hering
has been really pleased with how the deer’s necks look with the identification
collars, there is far less chafing than with the much looser GPS collars used
on the original control group!
Our original control group of 20 (down to 17 due to mortalities)
were wearing GPS collars (those loose ones with the big bling!) that were timed
to automatically drop off this February and March. Due to an unexpected provincial requirement
that delayed immuno-contraception by a year, we need a control group for at
least another year. So, as the original
collars “blow” off, we re-captured some of the same animals (and in some cases
new animals), for 18 does in total, and fit them with new colourful marker collars. These collars are even more light weight than
the originals, have only 2 smaller tags, and were provided to us by Margo
a family-owned and operated company with over 35 years of safe, effective,
non-lethal wildlife management solutions.
We have loved the privilege of working with Margo Supplies.
If you see an animal with pink tags on her collar you will
know that she is a control animal and was not given contraception this
Impact of COVID-19
Although we had hoped to re-mark 20 does and do a few more
collar checks (we’ve also been taking a blood sample to help determine
pregnancy rates, results not in), due to COVID-19 and the health guidelines for
physical distancing, we have wrapped up field work until September 2020 when we
will head out again to booster the does that received IC in the Fall of 2019,
and give a primary vaccine to up to 60 new does.
In the meantime, we hope you and your families and friends keep
healthy and safe.
Dr. Jason Fisher, lead scientist of the Oak Bay Urban Deer Research Project.
The current Oak Bay Urban Deer Research Project has been funded by the Province of BC and the District of Oak Bay, in partnership with the volunteer, non-profit Urban Wildlife Stewardship Society.
We’re so pleased that the Province has once again provided a grant through the Provincial Urban Deer Cost-Share Program , this year in the amount of $42,366.00, to support the continuation of this important deer management initiative.
The grant will, as stated by the District of Oak Bay, “enable (the district) to continue its partnership with the Urban Wildlife Stewardship Society (UWSS) to deliver research-informed urban deer immuno-contraception. Work in 2020 will include re-marking the control group, re-boostering does vaccinated in 2019, administering further primary vaccinations and boosters and collecting and further analyzing data”. This will include post-IC data.
When you think of deer, do you think of a doe feeding in a wilderness meadow, the Disney movie Bambi, or of the light-up decorations that were on display over Christmastime in front yards across Canada? For many people, deer are just that—something far away, a cartoon, or merely an inanimate decoration. However, in some cities in British Columbia, deer are a common, yet divisive, part of the urban landscape.
The native Columbia black-tailed deer (CBTD; a more docile sub-species of the mule deer found on the mainland), has coexisted on the landscape with humans for millennia. The First Nations of southern Vancouver Island used fire for land management that promoted the growth of important food plants like camas and would attract game species like CBTD. However, in the years since European colonization, southern Vancouver Island has grown into 13 municipal districts with a population of over 400,000 people. With the ensuing urban development, suburban sprawl, fire suppression, and predator exclusion has combined to change ecosystem dynamics and species distributions.
Coexistence with humans has resulted in habitat fragmentation, with a whopping 1,807 species at risk of extinction in BC, and over 110 of those species in southern Vancouver Island alone. However, some species do well coexisting with humans, like raccoons and deer—which can interact with humans and their property often enough to be considered nuisances. But are these now urban wildlife too numerous and running amok amidst the city backdrop, or is this actually bad press?
Just where are the deer?
The District of Oak Bay has been in the news often about a deer overpopulation problem. They’ve attempted a cull to manage deer populations, but as found in other municipalities, the cull had no lasting impact on the deer population but it did garner a public outcry. Management of the urban deer population has been highly polarizing—some people want them to stay, some people want them completely gone—but the management of urban wildlife is predicated on the knowledge of population size.
can give wildly different estimates of the number of deer present in Oak Bay. Any
single human observer may see six deer in their yard one day and then none the
next—humans have a cognitive bias, the availability bias, whereby we note large groups without noting
all the absences in between—which inflates estimates. And, when trying to count
mobile species, you need to be sure that you’re not counting the same
individuals more than once. And if you don’t see a deer, can you be sure that
it’s actually not there as opposed to just hiding? Thankfully camera traps to
We divided the 10.5 km2 of Oak Bay into 400m grid cells, and we systematically placed one camera trap into each of those 39 grid cells. Each camera trap was a Bushnell infra-red remote digital camera, secured to a tree between 0.5-1.5 m above the ground. Human observers can miss deer that are well hidden or might miss them in time (e.g. once the observer goes home for the day). The motion-activated camera traps are able to take photos throughout the day, eliminating those kinds of errors. The systematic design we used also allows us to differentiate between areas with high numbers of deer and those without deer—and ensured we could collect multiple observations of the same individuals across space—allowing us to get a good idea of space use. In addition to the cameras, we put GPS collars on 20 does to get an idea of home range size in Oak Bay, but the GPS collars had double-duty, to “mark” our known deer population. By measuring how frequently we detected marked (collared) animals at a camera station, compared to the number of unmarked animals, we could get an accurate estimate of population size.
Combining this systematic camera trap design with GPS collars has allowed us to generate the first, precise and robust estimate of CBTD population size in Oak Bay’s history. So then, just how many deer are running rampant around Oak Bay? Our analyses tell us that there are just under 100 deer (97 is the median, 95% confidence intervals between 72-128) and that they aren’t distributed equally across the municipality. Most deer spent their time within a 0.14 km2 area, and the largest average area a deer would use is 0.64 km2—significantly smaller than the home ranges they would use in wild environments (~140 to 1,770 ha.). That tells us that Oak Bay residents are seeing the same deer over and over, rather than seeing hoards of deer just once as they migrate through a large area.
With a definitive understanding of how many deer actually reside within Oak Bay, and where they are concentrating within the municipality, management can now be tailored to be cost-effective and successful. This fall, we administered immunocontraceptive (IC) to 60 does, and in the spring of 2020, our camera traps will be able to tell us if this birth control method was successful. If only our control group of does have fawns at the heel on camera trap photos, then we should be able to conclude that IC can be effectively administered as a non-lethal urban wildlife management technique—for Oak Bay, the Capital Region District of Vancouver Island, and other municipalities across BC that are struggling with their own urban deer management. We’ll be looking forward to seeing what the spring 2020 camera trap photos will reveal!
This piece was reposted with permission from WildCAM.
As another year of changing seasons comes to a close, the UWSS would like to wish everyone a very Merry Christmas, Happy Hanukkah, or perhaps just simply a celebration of the beauty, peace and balance that we so often find in nature.
We are sharing this video that reminds us of the unseen movements of wildlife, captured by a camera similar to the ones used in the current urban deer project we are conducting.
May the next year bring joy and happiness to you all.
May the next year bring happiness and joy to you all.
Over the past two years, you may have got used to seeing 20 does wandering around with collars that have four large tags in a variety of colours hanging from their necks. These deer are the control group for the Oak Bay Urban Deer Research Project and the collars are equipped with GPS, which has allowed our research team to track the does and collect data on their movement patterns, numbers, density and more.
This fall, 60 does, not including the control group, received an immuno-contraceptive (IC) vaccine. In order to be able to evaluate the impact of IC on the deer population, these does were fitted with a simple collar, as well as ear tags. The collars and ear tags are colour coded in order to allow for individual identification and give our researchers precise information.
The two collars fit very differently. The 20 GPS collars are quite loose, to allow for movement of the collar when the deer are moving and eating, due to the GPS “box” and the tags.
The IC collars do not have a large GPS box on them, or tags. Instead, the identification system is based on the colour of the collars, and the colour of two numbered ear tags that were also put on the does (along with one small provincial tag). These collars fit high on the neck and are quite snug to reduce chafing – we are always looking for ways to ensure the comfort of the deer. The fit of these collars minimizes movement as it’s not necessary without the tags and GPS box. The collars fit like a dog collar, allowing for two/three fingers to slide comfortably under the collar. They were fitted very carefully by our wildlife veterinarian, Dr. Hering.
We have had a few concerned citizens contact us that the collars seem too tight, and that the neck of the doe is “bulging” over the collar. Dr. Hering followed up on one such sighting a few weeks ago, and he was still able to easily slide his fingers under the collar – it was just the winter fur that has grown in since the field work that made it look tighter. He was happy to report that the fur and skin under the collar were in good shape.
Despite the collars appearing very snug, a few of the collars may have still been loose enough to slip down the neck a little bit, in fact unintentionally tightening them. We don’t think this is an issue and that it’s still the fur that creates the illusion of the collars appearing overly tight. However we have really appreciated citizens taking photos and letting us know of their concerns so that we can follow up. We recently had a reporting of a doe in the Falkland area that Dr. Hering would like to check out. If you see her, please note the colour of her collar and ear tags and send us an email at firstname.lastname@example.org so that we can locate her and have Dr. Hering evaluate.
Some people have also expressed concern that the collars will tighten as young deer grow. The collars on younger deer were fitted a bit more loosely to allow for growing over the winter. The collars all have a “rot off” so that over time the elements will cause the material to break down and the collars will drop off. For more information on the collars please go to https://uwss.ca/faqs-about-collars/ .
As always, we are grateful for the involvement of the community in this project. Our goal is to provide evidence-based, scientific information without compromising the deer. Their well-being is our first priority. If you do see a doe that concerns you, please contact us. It would be very helpful if you could note the collar colour and ear tag colour/number if possible. If you can safely take a photo, that would also be very helpful.
The Climate Emergency has an impact on all of us, often in ways we don’t necessarily recognize. Alina Fisher, communications expert for the UWSS (UVic PhD student), is a signatory on the open letter in the journal BioScience, signed by 11,258 scientists from 153 countries, declaring “clearly and unequivocally that planet Earth is facing a climate emergency”.
We know that the climate emergency is necessitating change everywhere, including our local communities. For instance, while people are looking for deer resistant plants for their gardens, what is often actually occurring is that past staples of the garden are being replaced with drought resistant plants – often with a return to native plants.
Although the indigenous Black-tailed deer have always been here, we don’t know exactly why their numbers have increased. There is a common belief that loss of their natural habitat is one of the most likely culprits, but we can also infer that Climate Change has had an impact too, with one outcome being a longer fawning season.
These are questions that our own scientists and others seek the answers to, and we hope that the Oak Bay Urban Deer Research Project might help us answer some questions, and see how the Climate Emergency affects not just us, but the wildlife that we are learning to once again co-exist with. We’re grateful to Alina for helping to bridge the gap between understanding climate change and recognizing the impact in our communities.