WHAT KIND OF DEER LIVE IN OAK BAY?
HOW MANY DEER LIVE IN OAK BAY?
As reported in our UWSS 2019 Progress Report, there are about 100 deer in all of Oak Bay. This has been established using a combination of radio/GPS collars in conjunction with an array of motion-triggered wildlife cameras that allow us to calculate an accurate deer population size. This form of mark-recapture study allows us to capture photos of both tagged and untagged deer. If we want to know more about how many deer there are and where they live, we need to be able to track their movements. This is a standard approach to wildlife research used around the globe.
WHY ARE SOME DEER IN OAK BAY WEARING COLLARS?
Twenty does in Oak Bay were originally fitted with radio/GPS collars in 2018 in order to study their movement patterns and distribution. This has given us valuable insights into urban deer ecology. We replaced those collars in 2020 with unique tag/colour combinations so we know which deer have been treated with immuno-contraception (IC) or are part of our un-treated control group of deer. For more info check our blog.
DO THE COLLARS HURT THE DEER?
The 20 GPS collars we originally used weighed less than 1 pound, and did not impact collared deer in any significant negative way. Those collars have since been replaced with coloured collar/tag combinations that are even more lightweight. There is no evidence that collars cause any harm to the animal. However, we take all reports of collar-induced injury seriously and consult with our wildlife veterinarian immediately.
WHAT IS IMMUNO-CONTRACEPTION (IC)?
WHY IMMUNO-CONTRACEPTION (IC) AND NOT A CULL OR TRANSLOCATION?
Experience in other jurisdictions has shown that translocation, i.e. trapping and moving animals to other areas, is not always effective (many animals move back to urban environments) and detrimental to the deer (poor survival statistics in an unaccustomed environment).
In a lethal cull, deer are caught in baited net traps, stunned with a bolt gun to the skull and the throat is slit until death from bleeding. Culls are not supported by the BCSPCA. Culls have also been shown to actually increase the local deer population. A program in Kelowna has demonstrated that after five years of culling, the deer population is now 36% higher than before their removal.
Once deer are removed from the population – through either culls or translocations – deer from neighbouring areas move into the now available habitat.
On the other hand, IC-vaccinated deer will maintain their home ranges, deterring inward migration. IC-vaccination may also reduce the number of “aggressive deer” because vaccinated does won’t have fawns to defend. And does that aren’t lactating eat less.
WHY DON'T WE STERILIZE BUCKS INSTEAD?
Each doe has the ability to produce one or two fawns each year. Sterilizing bucks isn’t a great solution because deer are not a monogamous species. If we miss sterilizing just one buck, that male could impregnate all of the does, having no impact on population growth. For each doe that we give contraception to, we’re decreasing the coming year’s fawn population by 1 or 2 animals. Thus females hold the key to population growth.
HOW ARE DEER CAPTURED AND TREATED WITH THE CONTRACEPTIVE VACCINE?
WHEN WILL OAK BAY DEER BE TREATED WITH IMMUNO-CONTRACEPTIVE VACCINE?
The first immuno-contraception (IC) treatments took place in the early fall 2019, and the next IC treatment will take place in the fall of 2020.
Fawns are typically born late May through June, although late-comers can be born throughout the summer. We will avoid the stress of handling any does and fawns during this critical period. However, IC needs to be administered before the rutting and mating season in November.
HOW QUICKLY WILL THE OAK BAY DEER POPULATION DECLINE AFTER IMMUNO-CONTRACEPTION?
That depends on what proportion of the deer population is treated. In 2019, we were able to administer immuno-contraception (IC) to 60 does in Oak Bay. Our 2019 permit allowed us to administer IC to up to 80 does in Oak Bay—but we could only find 60 to treat that were not part of our control group—since preliminary analysis estimates the number of deer at 97, we expect that represents nearly complete coverage. The 2020 permit allows for the same number of does to be given IC this fall.